[1/5] drm: add interface to get drm devices on the system v2

Commit Message

Jammy Zhou Aug. 13, 2015, 3:33 a.m. UTC

From: Emil Velikov <[e-mail]>

For mutiple GPU support, the devices on the system should be enumerated
to get necessary information about each device, and the drmGetDevices
interface is added for this. Currently only PCI devices are supported for
the enumeration.

Typical usage:
int count;
drmDevicePtr *foo;
count = drmGetDevices(NULL, 0);
foo = calloc(count, sizeof(drmDevicePtr));
count = drmGetDevices(foo, count);
/* find proper device, open correct device node, etc */
drmFreeDevices(foo, count);
free(foo);

v2: change according to feedback from Emil

Signed-off-by: Jammy Zhou <[e-mail]>
---
 xf86drm.c | 351 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 xf86drm.h |  34 ++++++
 2 files changed, 385 insertions(+)

Comments

Emil Velikov Aug. 13, 2015, 1:58 p.m. UTC | #1

On 13 August 2015 at 04:33, Jammy Zhou <[e-mail]> wrote:
> From: Emil Velikov <[e-mail]>
>
> For mutiple GPU support, the devices on the system should be enumerated
> to get necessary information about each device, and the drmGetDevices
> interface is added for this. Currently only PCI devices are supported for
> the enumeration.
>
If there are any other devices they will still be counted when
drmGetDevices(NULL, 0)... Is that intentional ?


> +static int drmParsePciDeviceInfo(const char *config,
> +                                 drmPciDeviceInfoPtr device)
> +{
> +    if (config == NULL)
> +        return -EINVAL;
> +
> +    device->vendor_id = config[0] | (config[1] << 8);
> +    device->device_id = config[2] | (config[3] << 8);
> +    device->revision_id = config[8];
> +    device->subvendor_id = config[44] | (config[45] << 8);
> +    device->subdevice_id = config[46] | (config[47] << 8);
> +
Something funny is happening here - on my intel system vendor_id is
reported as 0xff86, instead of 0x8086. Subvendor/device are also
messed up - ffaa and ffda instead of 17aa + 21da.

One could bikeshed on the de-duplication error path(s), but
considering that things work and there are no leaks we can leave that
for some other day.

-Emil

Daniel Vetter Aug. 13, 2015, 3:07 p.m. UTC | #2

On Thu, Aug 13, 2015 at 11:33:41AM +0800, Jammy Zhou wrote:
> From: Emil Velikov <[e-mail]>
> 
> For mutiple GPU support, the devices on the system should be enumerated
> to get necessary information about each device, and the drmGetDevices
> interface is added for this. Currently only PCI devices are supported for
> the enumeration.
> 
> Typical usage:
> int count;
> drmDevicePtr *foo;
> count = drmGetDevices(NULL, 0);
> foo = calloc(count, sizeof(drmDevicePtr));
> count = drmGetDevices(foo, count);
> /* find proper device, open correct device node, etc */
> drmFreeDevices(foo, count);
> free(foo);
> 
> v2: change according to feedback from Emil
> 
> Signed-off-by: Jammy Zhou <[e-mail]>
> ---
>  xf86drm.c | 351 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  xf86drm.h |  34 ++++++
>  2 files changed, 385 insertions(+)
> 
> diff --git a/xf86drm.c b/xf86drm.c
> index 5e02969..237663b 100644
> --- a/xf86drm.c
> +++ b/xf86drm.c
> @@ -55,6 +55,7 @@
>  #ifdef HAVE_SYS_MKDEV_H
>  # include <sys/mkdev.h> /* defines major(), minor(), and makedev() on Solaris */
>  #endif
> +#include <math.h>
>  
>  /* Not all systems have MAP_FAILED defined */
>  #ifndef MAP_FAILED
> @@ -2829,3 +2830,353 @@ char *drmGetRenderDeviceNameFromFd(int fd)
>  {
>  	return drmGetMinorNameForFD(fd, DRM_NODE_RENDER);
>  }
> +
> +#ifdef __linux__
> +static int drmParseSubsystemType(const char *str)
> +{
> +    char link[PATH_MAX + 1] = "";
> +    char *name;
> +
> +    if (readlink(str, link, PATH_MAX) < 0)
> +        return -EINVAL;
> +
> +    name = strrchr(link, '/');
> +    if (!name)
> +        return -EINVAL;
> +
> +    name++;
> +
> +    if (strncmp(name, "pci", 3) == 0)
> +        return DRM_BUS_PCI;
> +
> +    return -EINVAL;
> +}
> +
> +static int drmParsePciBusInfo(const char *str, drmPciBusInfoPtr info)
> +{
> +    int domain, bus, dev, func;
> +    char *value;
> +
> +    if (str == NULL)
> +        return -EINVAL;
> +
> +    value = strstr(str, "PCI_SLOT_NAME=");
> +    if (value == NULL)
> +        return -EINVAL;
> +
> +    value += strlen("PCI_SLOT_NAME=");
> +
> +    if (sscanf(value, "%04x:%02x:%02x.%1u",
> +               &domain, &bus, &dev, &func) != 4)
> +        return -EINVAL;
> +
> +    info->domain = domain;
> +    info->bus = bus;
> +    info->dev = dev;
> +    info->func = func;
> +
> +    return 0;
> +}
> +
> +static int drmSameDevice(drmDevicePtr a, drmDevicePtr b)
> +{
> +    if (a->bustype != b->bustype)
> +        return 0;
> +
> +    switch (a->bustype) {
> +    case DRM_BUS_PCI:
> +        if (memcmp(a->businfo.pci, b->businfo.pci, sizeof(drmPciBusInfo)) == 0)
> +            return 1;
> +    default:
> +        break;
> +    }
> +
> +    return 0;
> +}
> +
> +static int drmGetNodeType(const char *name)
> +{
> +    if (strncmp(name, DRM_PRIMARY_MINOR_NAME,
> +        sizeof(DRM_PRIMARY_MINOR_NAME) - 1) == 0)
> +        return DRM_NODE_PRIMARY;
> +
> +    if (strncmp(name, DRM_CONTROL_MINOR_NAME,
> +        sizeof(DRM_CONTROL_MINOR_NAME ) - 1) == 0)
> +        return DRM_NODE_CONTROL;
> +
> +    if (strncmp(name, DRM_RENDER_MINOR_NAME,
> +        sizeof(DRM_RENDER_MINOR_NAME) - 1) == 0)
> +        return DRM_NODE_RENDER;
> +
> +    return -EINVAL;
> +}
> +
> +static int drmParsePciDeviceInfo(const char *config,
> +                                 drmPciDeviceInfoPtr device)
> +{
> +    if (config == NULL)
> +        return -EINVAL;
> +
> +    device->vendor_id = config[0] | (config[1] << 8);
> +    device->device_id = config[2] | (config[3] << 8);
> +    device->revision_id = config[8];
> +    device->subvendor_id = config[44] | (config[45] << 8);
> +    device->subdevice_id = config[46] | (config[47] << 8);

Why not reuse libpciaccess?
-Daniel

> +
> +    return 0;
> +}
> +
> +static void drmFreeDevice(drmDevicePtr device)
> +{
> +    int i;
> +
> +    if (device == NULL)
> +        return;
> +
> +    if (device->nodes != NULL)
> +        for (i = 0; i < DRM_NODE_MAX; i++)
> +            free(device->nodes[i]);
> +
> +    free(device->nodes);
> +    free(device->businfo.pci);
> +    free(device->deviceinfo.pci);
> +}
> +
> +void drmFreeDevices(drmDevicePtr devices[], int count)
> +{
> +    int i;
> +
> +    if (devices == NULL)
> +        return;
> +
> +    for (i = 0; i < count; i++) {
> +        drmFreeDevice(devices[i]);
> +        free(devices[i]);
> +        devices[i] = NULL;
> +    }
> +}
> +
> +/**
> + * Get drm devices on the system
> + *
> + * \param devices the array of devices with drmDevicePtr elements
> + *                can be NULL to get the device number first
> + * \param max_devices the maximum number of devices for the array
> + *
> + * \return on error - negative error code,
> + *         if devices is NULL - total number of devices available on the system,
> + *         alternatively the number of devices stored in devices[], which is
> + *         capped by the max_devices.
> + */
> +int drmGetDevices(drmDevicePtr devices[], int max_devices)
> +{
> +    drmDevicePtr devs = NULL;
> +    drmPciBusInfoPtr pcibus = NULL;
> +    drmPciDeviceInfoPtr pcidevice = NULL;
> +    DIR *sysdir = NULL;
> +    struct dirent *dent = NULL;
> +    struct stat sbuf = {0};
> +    char node[PATH_MAX + 1] = "";
> +    char path[PATH_MAX + 1] = "";
> +    char data[128] = "";
> +    char config[64] = "";
> +    int node_type, subsystem_type;
> +    int maj, min;
> +    int fd;
> +    int ret, i = 0, j, node_count, device_count = 0;
> +    int max_count = 16;
> +    int *duplicated = NULL;
> +
> +    devs = calloc(max_count, sizeof(*devs));
> +    if (devs == NULL)
> +        return -ENOMEM;
> +
> +    sysdir = opendir(DRM_DIR_NAME);
> +    if (!sysdir) {
> +        ret = -errno;
> +        goto free_locals;
> +    }
> +
> +    while ((dent = readdir(sysdir))) {
> +        node_type = drmGetNodeType(dent->d_name);
> +        if (node_type < 0)
> +            continue;
> +
> +        snprintf(node, PATH_MAX, "%s/%s", DRM_DIR_NAME, dent->d_name);
> +        if (stat(node, &sbuf))
> +            continue;
> +
> +        maj = major(sbuf.st_rdev);
> +        min = minor(sbuf.st_rdev);
> +
> +        if (maj != DRM_MAJOR || !S_ISCHR(sbuf.st_mode))
> +            continue;
> +
> +        snprintf(path, PATH_MAX, "/sys/dev/char/%d:%d/device/subsystem",
> +                 maj, min);
> +        subsystem_type = drmParseSubsystemType(path);
> +
> +        if (subsystem_type < 0)
> +            continue;
> +
> +        switch (subsystem_type) {
> +        case DRM_BUS_PCI:
> +            pcibus = calloc(1, sizeof(*pcibus));
> +            if (pcibus == NULL) {
> +                ret = -ENOMEM;
> +                goto free_locals;
> +            }
> +
> +            snprintf(path, PATH_MAX, "/sys/dev/char/%d:%d/device/uevent",
> +                     maj, min);
> +            fd = open(path, O_RDONLY);
> +            if (fd < 0) {
> +                ret = -errno;
> +                goto free_locals;
> +            }
> +            ret = read(fd, data, sizeof(data));
> +            if (ret < 0) {
> +                ret = -errno;
> +                close(fd);
> +                goto free_locals;
> +            }
> +
> +            ret = drmParsePciBusInfo(data, pcibus);
> +            close(fd);
> +            if (ret)
> +                goto free_locals;
> +
> +            if (i >= max_count) {
> +                max_count += 16;
> +                devs = realloc(devs, max_count * sizeof(*devs));
> +            }
> +
> +            devs[i].businfo.pci = pcibus;
> +            devs[i].bustype = subsystem_type;
> +            devs[i].nodes = calloc(DRM_NODE_MAX, sizeof(char *));
> +            if (devs[i].nodes == NULL) {
> +                ret = -ENOMEM;
> +                goto free_locals;
> +            }
> +            devs[i].nodes[node_type] = strdup(node);
> +            if (devs[i].nodes[node_type] == NULL) {
> +                ret = -ENOMEM;
> +                goto free_locals;
> +            }
> +            devs[i].available_nodes = 1 << node_type;
> +
> +            if (devices != NULL) {
> +                snprintf(path, PATH_MAX, "/sys/class/drm/%s/device/config",
> +                         dent->d_name);
> +                fd = open(path, O_RDONLY);
> +                if (fd < 0) {
> +                     ret = -errno;
> +                     goto free_locals;
> +                }
> +                ret = read(fd, config, 64);
> +                if (ret < 0) {
> +                    ret = -errno;
> +                    close(fd);
> +                    goto free_locals;
> +                }
> +
> +                pcidevice = calloc(1, sizeof(*pcidevice));
> +                if (pcidevice == NULL) {
> +                    ret = -ENOMEM;
> +                    goto free_locals;
> +                }
> +
> +                ret = drmParsePciDeviceInfo(config, pcidevice);
> +                if (ret)
> +                    goto free_locals;
> +
> +                devs[i].deviceinfo.pci = pcidevice;
> +                close(fd);
> +            }
> +            break;
> +        default:
> +            fprintf(stderr, "The subsystem type is not supported yet\n");
> +            break;
> +        }
> +        i++;
> +    }
> +
> +    node_count = i;
> +
> +    /* merge duplicated devices with same domain/bus/device/func IDs */
> +    duplicated = calloc(node_count, sizeof(*duplicated));
> +    if (duplicated == NULL) {
> +        ret = -ENOMEM;
> +        goto free_locals;
> +    }
> +
> +    for (i = 0; i < node_count; i++) {
> +        for (j = i+1; j < node_count; j++) {
> +            if (duplicated[i] || duplicated[j])
> +                continue;
> +            if (drmSameDevice(&devs[i], &devs[j])) {
> +                duplicated[j] = 1;
> +                devs[i].available_nodes |= devs[j].available_nodes;
> +                node_type = log2(devs[j].available_nodes);
> +                devs[i].nodes[node_type] = devs[j].nodes[node_type];
> +                free(devs[j].nodes);
> +                free(devs[j].businfo.pci);
> +                free(devs[j].deviceinfo.pci);
> +            }
> +        }
> +    }
> +
> +    for (i = 0; i < node_count; i++) {
> +        if(duplicated[i] == 0) {
> +            if ((devices != NULL) && (device_count < max_devices)) {
> +                devices[device_count] = calloc(1, sizeof(drmDevice));
> +                if (devices[device_count] == NULL) {
> +                    ret = -ENOMEM;
> +                    break;
> +                }
> +                memcpy(devices[device_count], &devs[i], sizeof(drmDevice));
> +            } else
> +                drmFreeDevice(&devs[i]);
> +            device_count++;
> +        }
> +    }
> +
> +    if (i < node_count) {
> +        drmFreeDevices(devices, device_count);
> +        for ( ; i < node_count; i++)
> +            if(duplicated[i] == 0)
> +                drmFreeDevice(&devs[i]);
> +    } else
> +        ret = device_count;
> +
> +    free(duplicated);
> +    free(devs);
> +    closedir(sysdir);
> +    return ret;
> +
> +free_locals:
> +    for (j = 0; j < i; j++)
> +        drmFreeDevice(&devs[j]);
> +    free(pcidevice);
> +    free(pcibus);
> +    free(devs);
> +    closedir(sysdir);
> +    return ret;
> +}
> +#else
> +void drmFreeDevices(drmDevicePtr devices[], int count)
> +{
> +    (void)devices;
> +    (void)count;
> +}
> +
> +int drmGetDevices(drmDevicePtr devices[], int max_devices)
> +{
> +    (void)devices;
> +    (void)max_devices;
> +    return -EINVAL;
> +}
> +
> +#warning "Missing implementation of drmGetDevices/drmFreeDevices"
> +
> +#endif
> diff --git a/xf86drm.h b/xf86drm.h
> index 360e04a..e82ca84 100644
> --- a/xf86drm.h
> +++ b/xf86drm.h
> @@ -563,6 +563,8 @@ extern int           drmOpen(const char *name, const char *busid);
>  #define DRM_NODE_PRIMARY 0
>  #define DRM_NODE_CONTROL 1
>  #define DRM_NODE_RENDER  2
> +#define DRM_NODE_MAX     3
> +
>  extern int           drmOpenWithType(const char *name, const char *busid,
>                                       int type);
>  
> @@ -759,6 +761,38 @@ extern int drmPrimeFDToHandle(int fd, int prime_fd, uint32_t *handle);
>  extern char *drmGetPrimaryDeviceNameFromFd(int fd);
>  extern char *drmGetRenderDeviceNameFromFd(int fd);
>  
> +#define DRM_BUS_PCI   0
> +
> +typedef struct _drmPciBusInfo {
> +    uint16_t domain;
> +    uint8_t bus;
> +    uint8_t dev;
> +    uint8_t func;
> +} drmPciBusInfo, *drmPciBusInfoPtr;
> +
> +typedef struct _drmPciDeviceInfo {
> +    uint16_t vendor_id;
> +    uint16_t device_id;
> +    uint16_t subvendor_id;
> +    uint16_t subdevice_id;
> +    uint8_t revision_id;
> +} drmPciDeviceInfo, *drmPciDeviceInfoPtr;
> +
> +typedef struct _drmDevice {
> +    char **nodes; /* DRM_NODE_MAX sized array */
> +    int available_nodes; /* DRM_NODE_* bitmask */
> +    int bustype;
> +    union {
> +        drmPciBusInfoPtr pci;
> +    } businfo;
> +    union {
> +        drmPciDeviceInfoPtr pci;
> +    } deviceinfo;
> +} drmDevice, *drmDevicePtr;
> +
> +extern int drmGetDevices(drmDevicePtr devices[], int max_devices);
> +extern void drmFreeDevices(drmDevicePtr devices[], int count);
> +
>  #if defined(__cplusplus)
>  }
>  #endif
> -- 
> 1.9.1
> 
> _______________________________________________
> dri-devel mailing list
> [e-mail]
> http://lists.freedesktop.org/mailman/listinfo/dri-devel

Emil Velikov Aug. 13, 2015, 3:26 p.m. UTC | #3

On 13 August 2015 at 16:07, Daniel Vetter <[e-mail]> wrote:
> On Thu, Aug 13, 2015 at 11:33:41AM +0800, Jammy Zhou wrote:
>> From: Emil Velikov <[e-mail]>
>>
>> For mutiple GPU support, the devices on the system should be enumerated
>> to get necessary information about each device, and the drmGetDevices
>> interface is added for this. Currently only PCI devices are supported for
>> the enumeration.
>>
>> Typical usage:
>> int count;
>> drmDevicePtr *foo;
>> count = drmGetDevices(NULL, 0);
>> foo = calloc(count, sizeof(drmDevicePtr));
>> count = drmGetDevices(foo, count);
>> /* find proper device, open correct device node, etc */
>> drmFreeDevices(foo, count);
>> free(foo);
>>
>> v2: change according to feedback from Emil
>>
>> Signed-off-by: Jammy Zhou <[e-mail]>
>> ---
>>  xf86drm.c | 351 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>  xf86drm.h |  34 ++++++
>>  2 files changed, 385 insertions(+)
>>
>> diff --git a/xf86drm.c b/xf86drm.c
>> index 5e02969..237663b 100644
>> --- a/xf86drm.c
>> +++ b/xf86drm.c
>> @@ -55,6 +55,7 @@
>>  #ifdef HAVE_SYS_MKDEV_H
>>  # include <sys/mkdev.h> /* defines major(), minor(), and makedev() on Solaris */
>>  #endif
>> +#include <math.h>
>>
>>  /* Not all systems have MAP_FAILED defined */
>>  #ifndef MAP_FAILED
>> @@ -2829,3 +2830,353 @@ char *drmGetRenderDeviceNameFromFd(int fd)
>>  {
>>       return drmGetMinorNameForFD(fd, DRM_NODE_RENDER);
>>  }
>> +
>> +#ifdef __linux__
>> +static int drmParseSubsystemType(const char *str)
>> +{
>> +    char link[PATH_MAX + 1] = "";
>> +    char *name;
>> +
>> +    if (readlink(str, link, PATH_MAX) < 0)
>> +        return -EINVAL;
>> +
>> +    name = strrchr(link, '/');
>> +    if (!name)
>> +        return -EINVAL;
>> +
>> +    name++;
>> +
>> +    if (strncmp(name, "pci", 3) == 0)
>> +        return DRM_BUS_PCI;
>> +
>> +    return -EINVAL;
>> +}
>> +
>> +static int drmParsePciBusInfo(const char *str, drmPciBusInfoPtr info)
>> +{
>> +    int domain, bus, dev, func;
>> +    char *value;
>> +
>> +    if (str == NULL)
>> +        return -EINVAL;
>> +
>> +    value = strstr(str, "PCI_SLOT_NAME=");
>> +    if (value == NULL)
>> +        return -EINVAL;
>> +
>> +    value += strlen("PCI_SLOT_NAME=");
>> +
>> +    if (sscanf(value, "%04x:%02x:%02x.%1u",
>> +               &domain, &bus, &dev, &func) != 4)
>> +        return -EINVAL;
>> +
>> +    info->domain = domain;
>> +    info->bus = bus;
>> +    info->dev = dev;
>> +    info->func = func;
>> +
>> +    return 0;
>> +}
>> +
>> +static int drmSameDevice(drmDevicePtr a, drmDevicePtr b)
>> +{
>> +    if (a->bustype != b->bustype)
>> +        return 0;
>> +
>> +    switch (a->bustype) {
>> +    case DRM_BUS_PCI:
>> +        if (memcmp(a->businfo.pci, b->businfo.pci, sizeof(drmPciBusInfo)) == 0)
>> +            return 1;
>> +    default:
>> +        break;
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +static int drmGetNodeType(const char *name)
>> +{
>> +    if (strncmp(name, DRM_PRIMARY_MINOR_NAME,
>> +        sizeof(DRM_PRIMARY_MINOR_NAME) - 1) == 0)
>> +        return DRM_NODE_PRIMARY;
>> +
>> +    if (strncmp(name, DRM_CONTROL_MINOR_NAME,
>> +        sizeof(DRM_CONTROL_MINOR_NAME ) - 1) == 0)
>> +        return DRM_NODE_CONTROL;
>> +
>> +    if (strncmp(name, DRM_RENDER_MINOR_NAME,
>> +        sizeof(DRM_RENDER_MINOR_NAME) - 1) == 0)
>> +        return DRM_NODE_RENDER;
>> +
>> +    return -EINVAL;
>> +}
>> +
>> +static int drmParsePciDeviceInfo(const char *config,
>> +                                 drmPciDeviceInfoPtr device)
>> +{
>> +    if (config == NULL)
>> +        return -EINVAL;
>> +
>> +    device->vendor_id = config[0] | (config[1] << 8);
>> +    device->device_id = config[2] | (config[3] << 8);
>> +    device->revision_id = config[8];
>> +    device->subvendor_id = config[44] | (config[45] << 8);
>> +    device->subdevice_id = config[46] | (config[47] << 8);
>
> Why not reuse libpciaccess?
I fully agree that the implementation is not pretty, although...

Adding dependencies for optional new features doesn't seem too
appealing, either. It will also save us some headaches when someone
starts shipping libpciaccess.so with their binary game/program (just
like libudev is today).

Would be great if we can use libudev but... just not yet.

If you have any other ideas/suggestions please fire away.

Thanks
Emi

Jammy Zhou Aug. 14, 2015, 5:53 a.m. UTC | #4

Hi Emil,

> If there are any other devices they will still be counted when drmGetDevices(NULL, 0)... Is that intentional ?

Yes, I think so, so that this interface can support different kinds of devices in the future. For example, we have some ARM platforms supporting PCIE, in which case we can connect one PCIE graphics card, then there will be one GPU with the platform bus (integrated GPU in the ARM SOC), and one discrete GPU on the PCIE bus. 

> Something funny is happening here - on my intel system vendor_id is reported as 0xff86, instead of 0x8086. Subvendor/device are also messed up - ffaa and ffda instead of 17aa + 21da.

That's really interesting. Did you try to update the system BIOS?

Regards,
Jammy

-----Original Message-----
From: Emil Velikov [mailto:[e-mail]] 

Sent: Thursday, August 13, 2015 9:58 PM
To: Zhou, Jammy
Cc: ML dri-devel
Subject: Re: [PATCH 1/5] drm: add interface to get drm devices on the system v2

On 13 August 2015 at 04:33, Jammy Zhou <[e-mail]> wrote:
> From: Emil Velikov <[e-mail]>

>

> For mutiple GPU support, the devices on the system should be 

> enumerated to get necessary information about each device, and the 

> drmGetDevices interface is added for this. Currently only PCI devices 

> are supported for the enumeration.

>

If there are any other devices they will still be counted when drmGetDevices(NULL, 0)... Is that intentional ?


> +static int drmParsePciDeviceInfo(const char *config,

> +                                 drmPciDeviceInfoPtr device) {

> +    if (config == NULL)

> +        return -EINVAL;

> +

> +    device->vendor_id = config[0] | (config[1] << 8);

> +    device->device_id = config[2] | (config[3] << 8);

> +    device->revision_id = config[8];

> +    device->subvendor_id = config[44] | (config[45] << 8);

> +    device->subdevice_id = config[46] | (config[47] << 8);

> +

Something funny is happening here - on my intel system vendor_id is reported as 0xff86, instead of 0x8086. Subvendor/device are also messed up - ffaa and ffda instead of 17aa + 21da.

One could bikeshed on the de-duplication error path(s), but considering that things work and there are no leaks we can leave that for some other day.

-Emil

Jammy Zhou Aug. 14, 2015, 5:59 a.m. UTC | #5

We tried several different ways already for the enumeration interface (libpciaccess, libudev, etc). But we ran into some problems with these options for example when run Steam games which ships 32bit libraries (including libudev) in the steam runtime, so finally we decided to use sysfs directly to avoid introducing some additional dependencies into libdrm.

Regards,
Jammy

-----Original Message-----
From: Emil Velikov [mailto:[e-mail]] 

Sent: Thursday, August 13, 2015 11:27 PM
To: Daniel Vetter
Cc: Zhou, Jammy; ML dri-devel
Subject: Re: [PATCH 1/5] drm: add interface to get drm devices on the system v2

On 13 August 2015 at 16:07, Daniel Vetter <[e-mail]> wrote:
> On Thu, Aug 13, 2015 at 11:33:41AM +0800, Jammy Zhou wrote:

>> From: Emil Velikov <[e-mail]>

>>

>> For mutiple GPU support, the devices on the system should be 

>> enumerated to get necessary information about each device, and the 

>> drmGetDevices interface is added for this. Currently only PCI devices 

>> are supported for the enumeration.

>>

>> Typical usage:

>> int count;

>> drmDevicePtr *foo;

>> count = drmGetDevices(NULL, 0);

>> foo = calloc(count, sizeof(drmDevicePtr)); count = drmGetDevices(foo, 

>> count);

>> /* find proper device, open correct device node, etc */ 

>> drmFreeDevices(foo, count); free(foo);

>>

>> v2: change according to feedback from Emil

>>

>> Signed-off-by: Jammy Zhou <[e-mail]>

>> ---

>>  xf86drm.c | 351 

>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

>>  xf86drm.h |  34 ++++++

>>  2 files changed, 385 insertions(+)

>>

>> diff --git a/xf86drm.c b/xf86drm.c

>> index 5e02969..237663b 100644

>> --- a/xf86drm.c

>> +++ b/xf86drm.c

>> @@ -55,6 +55,7 @@

>>  #ifdef HAVE_SYS_MKDEV_H

>>  # include <sys/mkdev.h> /* defines major(), minor(), and makedev() 

>> on Solaris */  #endif

>> +#include <math.h>

>>

>>  /* Not all systems have MAP_FAILED defined */  #ifndef MAP_FAILED @@ 

>> -2829,3 +2830,353 @@ char *drmGetRenderDeviceNameFromFd(int fd)  {

>>       return drmGetMinorNameForFD(fd, DRM_NODE_RENDER);  }

>> +

>> +#ifdef __linux__

>> +static int drmParseSubsystemType(const char *str) {

>> +    char link[PATH_MAX + 1] = "";

>> +    char *name;

>> +

>> +    if (readlink(str, link, PATH_MAX) < 0)

>> +        return -EINVAL;

>> +

>> +    name = strrchr(link, '/');

>> +    if (!name)

>> +        return -EINVAL;

>> +

>> +    name++;

>> +

>> +    if (strncmp(name, "pci", 3) == 0)

>> +        return DRM_BUS_PCI;

>> +

>> +    return -EINVAL;

>> +}

>> +

>> +static int drmParsePciBusInfo(const char *str, drmPciBusInfoPtr 

>> +info) {

>> +    int domain, bus, dev, func;

>> +    char *value;

>> +

>> +    if (str == NULL)

>> +        return -EINVAL;

>> +

>> +    value = strstr(str, "PCI_SLOT_NAME=");

>> +    if (value == NULL)

>> +        return -EINVAL;

>> +

>> +    value += strlen("PCI_SLOT_NAME=");

>> +

>> +    if (sscanf(value, "%04x:%02x:%02x.%1u",

>> +               &domain, &bus, &dev, &func) != 4)

>> +        return -EINVAL;

>> +

>> +    info->domain = domain;

>> +    info->bus = bus;

>> +    info->dev = dev;

>> +    info->func = func;

>> +

>> +    return 0;

>> +}

>> +

>> +static int drmSameDevice(drmDevicePtr a, drmDevicePtr b) {

>> +    if (a->bustype != b->bustype)

>> +        return 0;

>> +

>> +    switch (a->bustype) {

>> +    case DRM_BUS_PCI:

>> +        if (memcmp(a->businfo.pci, b->businfo.pci, sizeof(drmPciBusInfo)) == 0)

>> +            return 1;

>> +    default:

>> +        break;

>> +    }

>> +

>> +    return 0;

>> +}

>> +

>> +static int drmGetNodeType(const char *name) {

>> +    if (strncmp(name, DRM_PRIMARY_MINOR_NAME,

>> +        sizeof(DRM_PRIMARY_MINOR_NAME) - 1) == 0)

>> +        return DRM_NODE_PRIMARY;

>> +

>> +    if (strncmp(name, DRM_CONTROL_MINOR_NAME,

>> +        sizeof(DRM_CONTROL_MINOR_NAME ) - 1) == 0)

>> +        return DRM_NODE_CONTROL;

>> +

>> +    if (strncmp(name, DRM_RENDER_MINOR_NAME,

>> +        sizeof(DRM_RENDER_MINOR_NAME) - 1) == 0)

>> +        return DRM_NODE_RENDER;

>> +

>> +    return -EINVAL;

>> +}

>> +

>> +static int drmParsePciDeviceInfo(const char *config,

>> +                                 drmPciDeviceInfoPtr device) {

>> +    if (config == NULL)

>> +        return -EINVAL;

>> +

>> +    device->vendor_id = config[0] | (config[1] << 8);

>> +    device->device_id = config[2] | (config[3] << 8);

>> +    device->revision_id = config[8];

>> +    device->subvendor_id = config[44] | (config[45] << 8);

>> +    device->subdevice_id = config[46] | (config[47] << 8);

>

> Why not reuse libpciaccess?

I fully agree that the implementation is not pretty, although...

Adding dependencies for optional new features doesn't seem too appealing, either. It will also save us some headaches when someone starts shipping libpciaccess.so with their binary game/program (just like libudev is today).

Would be great if we can use libudev but... just not yet.

If you have any other ideas/suggestions please fire away.

Thanks
Emi

Kai Wasserbäch Aug. 14, 2015, 7:59 a.m. UTC | #6

Zhou, Jammy wrote on 14.08.2015 07:59:
> We tried several different ways already for the enumeration interface (libpciaccess, libudev, etc). But we ran into some problems with these options for example when run Steam games which ships 32bit libraries (including libudev) in the steam runtime, so finally we decided to use sysfs directly to avoid introducing some additional dependencies into libdrm.

The reason sounds wrong. There was a similar discussion over at Mesa. I think
you (as in hardware/driver vendors like AMD/Intel/Nvidia) need to push Valve (or
the game devs through Valve or directly) to fix their setup. Steam runtime is
fine and all, but please only pre-load it, if needed (ie. library foo is missing
on the system and can't be installed through the package manager). IIRC the
VMWare guys said in the Mesa discussion, they have a script in place for their
virtualisation products, that checks whether a library needs to be loaded from
their "baseline directory" or from the system.

Working around a bug/design flaw in Steam's Linux version doesn't sound like a
supportable solution in the long run. As long as you let them get away with
that, you will face this problem over and over with different libraries. (For me
it's usually libstdc++ (needed by LLVM), libncurses and a few X(CB) libraries I
need to remove from Steam, before anything works. Though I do have script for
that, that I can run after every upgrade, this is not a solution for everyone.)

Cheers,
Kai

Emil Velikov Aug. 14, 2015, 8:17 a.m. UTC | #7

On 14 August 2015 at 08:59, Kai Wasserbäch <[e-mail]> wrote:
> Zhou, Jammy wrote on 14.08.2015 07:59:
>> We tried several different ways already for the enumeration interface (libpciaccess, libudev, etc). But we ran into some problems with these options for example when run Steam games which ships 32bit libraries (including libudev) in the steam runtime, so finally we decided to use sysfs directly to avoid introducing some additional dependencies into libdrm.
>
> The reason sounds wrong. There was a similar discussion over at Mesa. I think
> you (as in hardware/driver vendors like AMD/Intel/Nvidia) need to push Valve (or
> the game devs through Valve or directly) to fix their setup. Steam runtime is
> fine and all, but please only pre-load it, if needed (ie. library foo is missing
> on the system and can't be installed through the package manager). IIRC the
> VMWare guys said in the Mesa discussion, they have a script in place for their
> virtualisation products, that checks whether a library needs to be loaded from
> their "baseline directory" or from the system.
>
> Working around a bug/design flaw in Steam's Linux version doesn't sound like a
> supportable solution in the long run. As long as you let them get away with
> that, you will face this problem over and over with different libraries. (For me
> it's usually libstdc++ (needed by LLVM), libncurses and a few X(CB) libraries I
> need to remove from Steam, before anything works. Though I do have script for
> that, that I can run after every upgrade, this is not a solution for everyone.)
>
Helping and applying pressure to resolve the issue is the way to go.
But until that is resolved it's great to have a solution that does not
lead to a crash. It feels rude towards you and other users to
deliberately use the problematic combo and expect from you to remove
libfoo.so.

When things get sorted out, we can easily replace this (a tad ugly
implementation) with libudev.

-Emil

Kai Wasserbäch Aug. 14, 2015, 8:26 a.m. UTC | #8

Emil Velikov wrote on 14.08.2015 10:17:
> On 14 August 2015 at 08:59, Kai Wasserbäch <[e-mail]> wrote:
>> Zhou, Jammy wrote on 14.08.2015 07:59:
>>> We tried several different ways already for the enumeration interface (libpciaccess, libudev, etc). But we ran into some problems with these options for example when run Steam games which ships 32bit libraries (including libudev) in the steam runtime, so finally we decided to use sysfs directly to avoid introducing some additional dependencies into libdrm.
>>
>> The reason sounds wrong. There was a similar discussion over at Mesa. I think
>> you (as in hardware/driver vendors like AMD/Intel/Nvidia) need to push Valve (or
>> the game devs through Valve or directly) to fix their setup. Steam runtime is
>> fine and all, but please only pre-load it, if needed (ie. library foo is missing
>> on the system and can't be installed through the package manager). IIRC the
>> VMWare guys said in the Mesa discussion, they have a script in place for their
>> virtualisation products, that checks whether a library needs to be loaded from
>> their "baseline directory" or from the system.
>>
>> Working around a bug/design flaw in Steam's Linux version doesn't sound like a
>> supportable solution in the long run. As long as you let them get away with
>> that, you will face this problem over and over with different libraries. (For me
>> it's usually libstdc++ (needed by LLVM), libncurses and a few X(CB) libraries I
>> need to remove from Steam, before anything works. Though I do have script for
>> that, that I can run after every upgrade, this is not a solution for everyone.)
>>
> Helping and applying pressure to resolve the issue is the way to go.
> But until that is resolved it's great to have a solution that does not
> lead to a crash. It feels rude towards you and other users to
> deliberately use the problematic combo and expect from you to remove
> libfoo.so.

Well, I'd rather remove stuff from Steam's runtime than burden you and other
developers with maintaing code that is unnecessrily ugly. (Though that's
obviously just my opinion.)

> When things get sorted out, we can easily replace this (a tad ugly
> implementation) with libudev.

As long as you allow this behaviour by working around it, I don't see Valve/game
developers "invest" in a real solution (because it works now). Businesses
usually only move from a position, when there's outside pressure and a clear
advantage to do so (here: no bug reports about crashing games).

Anyway, this was just my two cents and you can obviously decide in any way you
deem to be the best.

Emil Velikov Aug. 14, 2015, 8:35 a.m. UTC | #9

On 14 August 2015 at 06:53, Zhou, Jammy <[e-mail]> wrote:
> Hi Emil,
>
>> If there are any other devices they will still be counted when drmGetDevices(NULL, 0)... Is that intentional ?
> Yes, I think so, so that this interface can support different kinds of devices in the future. For example, we have some ARM platforms supporting PCIE, in which case we can connect one PCIE graphics card, then there will be one GPU with the platform bus (integrated GPU in the ARM SOC), and one discrete GPU on the PCIE bus.
>
What is the point in claiming that you have X+Y devices, if the API
does not provide any information about Y of them ? It seems very
misleading imho.

>> Something funny is happening here - on my intel system vendor_id is reported as 0xff86, instead of 0x8086. Subvendor/device are also messed up - ffaa and ffda instead of 17aa + 21da.
> That's really interesting. Did you try to update the system BIOS?
>
Seems like a C Programming 101 issue to me rather than a BIOS one.The
(signed) char 0x86 gets extended/promoted to 0xff86 and then all hell
breaks loose. Adding typecast(s) should fix it. That does not excuse
me from writing is so weird from the start :)

Thanks for tweaking/ironing the bugs out.
Emil

Emil Velikov Aug. 14, 2015, 9:07 a.m. UTC | #10

On 14 August 2015 at 09:26, Kai Wasserbäch <[e-mail]> wrote:
> Emil Velikov wrote on 14.08.2015 10:17:
>> On 14 August 2015 at 08:59, Kai Wasserbäch <[e-mail]> wrote:
>>> Zhou, Jammy wrote on 14.08.2015 07:59:
>>>> We tried several different ways already for the enumeration interface (libpciaccess, libudev, etc). But we ran into some problems with these options for example when run Steam games which ships 32bit libraries (including libudev) in the steam runtime, so finally we decided to use sysfs directly to avoid introducing some additional dependencies into libdrm.
>>>
>>> The reason sounds wrong. There was a similar discussion over at Mesa. I think
>>> you (as in hardware/driver vendors like AMD/Intel/Nvidia) need to push Valve (or
>>> the game devs through Valve or directly) to fix their setup. Steam runtime is
>>> fine and all, but please only pre-load it, if needed (ie. library foo is missing
>>> on the system and can't be installed through the package manager). IIRC the
>>> VMWare guys said in the Mesa discussion, they have a script in place for their
>>> virtualisation products, that checks whether a library needs to be loaded from
>>> their "baseline directory" or from the system.
>>>
>>> Working around a bug/design flaw in Steam's Linux version doesn't sound like a
>>> supportable solution in the long run. As long as you let them get away with
>>> that, you will face this problem over and over with different libraries. (For me
>>> it's usually libstdc++ (needed by LLVM), libncurses and a few X(CB) libraries I
>>> need to remove from Steam, before anything works. Though I do have script for
>>> that, that I can run after every upgrade, this is not a solution for everyone.)
>>>
>> Helping and applying pressure to resolve the issue is the way to go.
>> But until that is resolved it's great to have a solution that does not
>> lead to a crash. It feels rude towards you and other users to
>> deliberately use the problematic combo and expect from you to remove
>> libfoo.so.
>
> Well, I'd rather remove stuff from Steam's runtime than burden you and other
> developers with maintaing code that is unnecessrily ugly. (Though that's
> obviously just my opinion.)
>
>> When things get sorted out, we can easily replace this (a tad ugly
>> implementation) with libudev.
>
> As long as you allow this behaviour by working around it,
There is a saying (roughly translated to) "The wiser man always steps
back". Or we could/should be like Linus - "F* you $company"

> I don't see Valve/game
> developers "invest" in a real solution (because it works now). Businesses
> usually only move from a position, when there's outside pressure and a clear
> advantage to do so (here: no bug reports about crashing games).
>
There have been plenty of reports opened wrt
libudev/libgcc_s/libstdc++ on their trackers and seemingly limited
interest to fix things.

This is a catch 20/20 afaics. "FOSS drivers do not work thus they are
s**t" is how a sizeable hunk of people think. They rarely consider
what the actual issue might be, because "I installed the nvidia/amd
proprietary drivers and things work now".

> Anyway, this was just my two cents and you can obviously decide in any way you
> deem to be the best.
>
Personally, I'd love if there was no "options" and we can just use
libfoo. Who knows Valve devs might get a wake up call and fix the
problem ?


-Emil
P.S. Fun fact: Valve's annual "TI" Dota2 tournament managed to
accumulate some 66 million USD gross income, over 100 days.

Jammy Zhou Aug. 14, 2015, 9:41 a.m. UTC | #11

> What is the point in claiming that you have X+Y devices, if the API does not provide any information about Y of them ? It seems very misleading imho.


I'm not sure if I understand your question correctly. Do you mean if the Y devices will be enumerated with current implementation? If so, I think the answer should be 'NO', since other bus types (i.e, platform, USB) are not supported yet.

Regards,
Jammy

-----Original Message-----
From: Emil Velikov [mailto:[e-mail]] 

Sent: Friday, August 14, 2015 4:35 PM
To: Zhou, Jammy
Cc: ML dri-devel
Subject: Re: [PATCH 1/5] drm: add interface to get drm devices on the system v2

On 14 August 2015 at 06:53, Zhou, Jammy <[e-mail]> wrote:
> Hi Emil,

>

>> If there are any other devices they will still be counted when drmGetDevices(NULL, 0)... Is that intentional ?

> Yes, I think so, so that this interface can support different kinds of devices in the future. For example, we have some ARM platforms supporting PCIE, in which case we can connect one PCIE graphics card, then there will be one GPU with the platform bus (integrated GPU in the ARM SOC), and one discrete GPU on the PCIE bus.

>

What is the point in claiming that you have X+Y devices, if the API does not provide any information about Y of them ? It seems very misleading imho.

>> Something funny is happening here - on my intel system vendor_id is reported as 0xff86, instead of 0x8086. Subvendor/device are also messed up - ffaa and ffda instead of 17aa + 21da.

> That's really interesting. Did you try to update the system BIOS?

>

Seems like a C Programming 101 issue to me rather than a BIOS one.The
(signed) char 0x86 gets extended/promoted to 0xff86 and then all hell breaks loose. Adding typecast(s) should fix it. That does not excuse me from writing is so weird from the start :)

Thanks for tweaking/ironing the bugs out.
Emil

Jammy Zhou Aug. 14, 2015, 9:48 a.m. UTC | #12

> There have been plenty of reports opened wrt libudev/libgcc_s/libstdc++ on their trackers and seemingly limited interest to fix things.


Yes, there are a bunch of issues reported for this already. But it looks like Valve has no plan to fix these issues. For example,
https://github.com/ValveSoftware/steam-runtime/issues/13

IMHO, we can probably use sysfs first, and when the issue is solved by Valve, we can switch to the udev solution later.

Regards,
Jammy

-----Original Message-----
From: Emil Velikov [mailto:[e-mail]] 

Sent: Friday, August 14, 2015 5:08 PM
To: Kai Wasserbäch
Cc: Zhou, Jammy; Daniel Vetter; ML dri-devel
Subject: Re: [PATCH 1/5] drm: add interface to get drm devices on the system v2

On 14 August 2015 at 09:26, Kai Wasserbäch <[e-mail]> wrote:
> Emil Velikov wrote on 14.08.2015 10:17:

>> On 14 August 2015 at 08:59, Kai Wasserbäch <[e-mail]> wrote:

>>> Zhou, Jammy wrote on 14.08.2015 07:59:

>>>> We tried several different ways already for the enumeration interface (libpciaccess, libudev, etc). But we ran into some problems with these options for example when run Steam games which ships 32bit libraries (including libudev) in the steam runtime, so finally we decided to use sysfs directly to avoid introducing some additional dependencies into libdrm.

>>>

>>> The reason sounds wrong. There was a similar discussion over at 

>>> Mesa. I think you (as in hardware/driver vendors like 

>>> AMD/Intel/Nvidia) need to push Valve (or the game devs through Valve 

>>> or directly) to fix their setup. Steam runtime is fine and all, but 

>>> please only pre-load it, if needed (ie. library foo is missing on 

>>> the system and can't be installed through the package manager). IIRC 

>>> the VMWare guys said in the Mesa discussion, they have a script in 

>>> place for their virtualisation products, that checks whether a library needs to be loaded from their "baseline directory" or from the system.

>>>

>>> Working around a bug/design flaw in Steam's Linux version doesn't 

>>> sound like a supportable solution in the long run. As long as you 

>>> let them get away with that, you will face this problem over and 

>>> over with different libraries. (For me it's usually libstdc++ 

>>> (needed by LLVM), libncurses and a few X(CB) libraries I need to 

>>> remove from Steam, before anything works. Though I do have script 

>>> for that, that I can run after every upgrade, this is not a solution 

>>> for everyone.)

>>>

>> Helping and applying pressure to resolve the issue is the way to go.

>> But until that is resolved it's great to have a solution that does 

>> not lead to a crash. It feels rude towards you and other users to 

>> deliberately use the problematic combo and expect from you to remove 

>> libfoo.so.

>

> Well, I'd rather remove stuff from Steam's runtime than burden you and 

> other developers with maintaing code that is unnecessrily ugly. 

> (Though that's obviously just my opinion.)

>

>> When things get sorted out, we can easily replace this (a tad ugly

>> implementation) with libudev.

>

> As long as you allow this behaviour by working around it,

There is a saying (roughly translated to) "The wiser man always steps back". Or we could/should be like Linus - "F* you $company"

> I don't see Valve/game

> developers "invest" in a real solution (because it works now). 

> Businesses usually only move from a position, when there's outside 

> pressure and a clear advantage to do so (here: no bug reports about crashing games).

>

There have been plenty of reports opened wrt libudev/libgcc_s/libstdc++ on their trackers and seemingly limited interest to fix things.

This is a catch 20/20 afaics. "FOSS drivers do not work thus they are s**t" is how a sizeable hunk of people think. They rarely consider what the actual issue might be, because "I installed the nvidia/amd proprietary drivers and things work now".

> Anyway, this was just my two cents and you can obviously decide in any 

> way you deem to be the best.

>

Personally, I'd love if there was no "options" and we can just use libfoo. Who knows Valve devs might get a wake up call and fix the problem ?


-Emil
P.S. Fun fact: Valve's annual "TI" Dota2 tournament managed to accumulate some 66 million USD gross income, over 100 days.

Emil Velikov Aug. 14, 2015, 10:05 a.m. UTC | #13

On 14 August 2015 at 10:41, Zhou, Jammy <[e-mail]> wrote:
>> What is the point in claiming that you have X+Y devices, if the API does not provide any information about Y of them ? It seems very misleading imho.
>
> I'm not sure if I understand your question correctly.
Easy - replace X with "pci" and Y with "platform/usb" :)

Or in other words:
user: "hey libdrm, how many devices do we have"
libdrm: "hey user, there are 10 devices here."
user: "great, tell me all about them"
libdrm: "sure... well I cannot tell you anything about 3 of them, but
the rest are fine"
user: "why did you stay that they are 10, if there is no info for 3 of them ?"

Fwiw it can be argued either way but I'd suspect that the current
behaviour is not too welcoming.

If people feel for the current behaviour I'kk be ok with it.

Thanks
Emil

Jammy Zhou Aug. 14, 2015, 12:15 p.m. UTC | #14

Okay, I got it. Actually with current implementation, only the number of PCI devices on the system is returned for drmGetDevices(NULL, 0). I extracted related code below. I hope it can address your concern :-)

+static int drmParseSubsystemType(const char *str) {
+    char link[PATH_MAX + 1] = "";
+    char *name;
+
+    if (readlink(str, link, PATH_MAX) < 0)
+        return -EINVAL;
+
+    name = strrchr(link, '/');
+    if (!name)
+        return -EINVAL;
+
+    name++;
+
+    if (strncmp(name, "pci", 3) == 0)
+        return DRM_BUS_PCI;
+
+    return -EINVAL;
+}
...
+        subsystem_type = drmParseSubsystemType(path);
+
+        if (subsystem_type < 0)
+            continue;

Regards,
Jammy

-----Original Message-----
From: Emil Velikov [mailto:[e-mail]] 

Sent: Friday, August 14, 2015 6:05 PM
To: Zhou, Jammy
Cc: ML dri-devel
Subject: Re: [PATCH 1/5] drm: add interface to get drm devices on the system v2

On 14 August 2015 at 10:41, Zhou, Jammy <[e-mail]> wrote:
>> What is the point in claiming that you have X+Y devices, if the API does not provide any information about Y of them ? It seems very misleading imho.

>

> I'm not sure if I understand your question correctly.

Easy - replace X with "pci" and Y with "platform/usb" :)

Or in other words:
user: "hey libdrm, how many devices do we have"
libdrm: "hey user, there are 10 devices here."
user: "great, tell me all about them"
libdrm: "sure... well I cannot tell you anything about 3 of them, but the rest are fine"
user: "why did you stay that they are 10, if there is no info for 3 of them ?"

Fwiw it can be argued either way but I'd suspect that the current behaviour is not too welcoming.

If people feel for the current behaviour I'kk be ok with it.

Thanks
Emil

Emil Velikov Aug. 14, 2015, 12:28 p.m. UTC | #15

On 14 August 2015 at 13:15, Zhou, Jammy <[e-mail]> wrote:
> Okay, I got it. Actually with current implementation, only the number of PCI devices on the system is returned for drmGetDevices(NULL, 0). I extracted related code below. I hope it can address your concern :-)
>
Had a blond moment and got confused with the subsystem_type default
statement. Please ignore my earlier rambling.

-Emil

Jammy Zhou Aug. 14, 2015, 12:45 p.m. UTC | #16

That's okay. Shall we get this patch merged now if no other objections?

Regards,
Jammy

-----Original Message-----
From: Emil Velikov [mailto:[e-mail]] 

Sent: Friday, August 14, 2015 8:29 PM
To: Zhou, Jammy
Cc: ML dri-devel
Subject: Re: [PATCH 1/5] drm: add interface to get drm devices on the system v2

On 14 August 2015 at 13:15, Zhou, Jammy <[e-mail]> wrote:
> Okay, I got it. Actually with current implementation, only the number 

> of PCI devices on the system is returned for drmGetDevices(NULL, 0). I 

> extracted related code below. I hope it can address your concern :-)

>

Had a blond moment and got confused with the subsystem_type default statement. Please ignore my earlier rambling.

-Emil

Emil Velikov Aug. 14, 2015, 1:19 p.m. UTC | #17

On 14/08/15 13:45, Zhou, Jammy wrote:
> That's okay. Shall we get this patch merged now if no other objections?
> 
First we should fix the funny vendor/device/etc id issue. Otherwise the
API is bugged badly.

-Emil

Jammy Zhou Aug. 14, 2015, 1:43 p.m. UTC | #18

Oh, I really missed that. I will get it resolved next week.

Regards,
Jammy

-----Original Message-----
From: Emil Velikov [mailto:[e-mail]] 

Sent: Friday, August 14, 2015 9:19 PM
To: Zhou, Jammy
Cc: [e-mail]; ML dri-devel
Subject: Re: [PATCH 1/5] drm: add interface to get drm devices on the system v2

On 14/08/15 13:45, Zhou, Jammy wrote:
> That's okay. Shall we get this patch merged now if no other objections?

> 

First we should fix the funny vendor/device/etc id issue. Otherwise the API is bugged badly.

-Emil

Patch

diff --git a/xf86drm.c b/xf86drm.c
index 5e02969..237663b 100644
--- a/xf86drm.c
+++ b/xf86drm.c
@@ -55,6 +55,7 @@ 
 #ifdef HAVE_SYS_MKDEV_H
 # include <sys/mkdev.h> /* defines major(), minor(), and makedev() on Solaris */
 #endif
+#include <math.h>
 
 /* Not all systems have MAP_FAILED defined */
 #ifndef MAP_FAILED
@@ -2829,3 +2830,353 @@  char *drmGetRenderDeviceNameFromFd(int fd)
 {
 	return drmGetMinorNameForFD(fd, DRM_NODE_RENDER);
 }
+
+#ifdef __linux__
+static int drmParseSubsystemType(const char *str)
+{
+    char link[PATH_MAX + 1] = "";
+    char *name;
+
+    if (readlink(str, link, PATH_MAX) < 0)
+        return -EINVAL;
+
+    name = strrchr(link, '/');
+    if (!name)
+        return -EINVAL;
+
+    name++;
+
+    if (strncmp(name, "pci", 3) == 0)
+        return DRM_BUS_PCI;
+
+    return -EINVAL;
+}
+
+static int drmParsePciBusInfo(const char *str, drmPciBusInfoPtr info)
+{
+    int domain, bus, dev, func;
+    char *value;
+
+    if (str == NULL)
+        return -EINVAL;
+
+    value = strstr(str, "PCI_SLOT_NAME=");
+    if (value == NULL)
+        return -EINVAL;
+
+    value += strlen("PCI_SLOT_NAME=");
+
+    if (sscanf(value, "%04x:%02x:%02x.%1u",
+               &domain, &bus, &dev, &func) != 4)
+        return -EINVAL;
+
+    info->domain = domain;
+    info->bus = bus;
+    info->dev = dev;
+    info->func = func;
+
+    return 0;
+}
+
+static int drmSameDevice(drmDevicePtr a, drmDevicePtr b)
+{
+    if (a->bustype != b->bustype)
+        return 0;
+
+    switch (a->bustype) {
+    case DRM_BUS_PCI:
+        if (memcmp(a->businfo.pci, b->businfo.pci, sizeof(drmPciBusInfo)) == 0)
+            return 1;
+    default:
+        break;
+    }
+
+    return 0;
+}
+
+static int drmGetNodeType(const char *name)
+{
+    if (strncmp(name, DRM_PRIMARY_MINOR_NAME,
+        sizeof(DRM_PRIMARY_MINOR_NAME) - 1) == 0)
+        return DRM_NODE_PRIMARY;
+
+    if (strncmp(name, DRM_CONTROL_MINOR_NAME,
+        sizeof(DRM_CONTROL_MINOR_NAME ) - 1) == 0)
+        return DRM_NODE_CONTROL;
+
+    if (strncmp(name, DRM_RENDER_MINOR_NAME,
+        sizeof(DRM_RENDER_MINOR_NAME) - 1) == 0)
+        return DRM_NODE_RENDER;
+
+    return -EINVAL;
+}
+
+static int drmParsePciDeviceInfo(const char *config,
+                                 drmPciDeviceInfoPtr device)
+{
+    if (config == NULL)
+        return -EINVAL;
+
+    device->vendor_id = config[0] | (config[1] << 8);
+    device->device_id = config[2] | (config[3] << 8);
+    device->revision_id = config[8];
+    device->subvendor_id = config[44] | (config[45] << 8);
+    device->subdevice_id = config[46] | (config[47] << 8);
+
+    return 0;
+}
+
+static void drmFreeDevice(drmDevicePtr device)
+{
+    int i;
+
+    if (device == NULL)
+        return;
+
+    if (device->nodes != NULL)
+        for (i = 0; i < DRM_NODE_MAX; i++)
+            free(device->nodes[i]);
+
+    free(device->nodes);
+    free(device->businfo.pci);
+    free(device->deviceinfo.pci);
+}
+
+void drmFreeDevices(drmDevicePtr devices[], int count)
+{
+    int i;
+
+    if (devices == NULL)
+        return;
+
+    for (i = 0; i < count; i++) {
+        drmFreeDevice(devices[i]);
+        free(devices[i]);
+        devices[i] = NULL;
+    }
+}
+
+/**
+ * Get drm devices on the system
+ *
+ * \param devices the array of devices with drmDevicePtr elements
+ *                can be NULL to get the device number first
+ * \param max_devices the maximum number of devices for the array
+ *
+ * \return on error - negative error code,
+ *         if devices is NULL - total number of devices available on the system,
+ *         alternatively the number of devices stored in devices[], which is
+ *         capped by the max_devices.
+ */
+int drmGetDevices(drmDevicePtr devices[], int max_devices)
+{
+    drmDevicePtr devs = NULL;
+    drmPciBusInfoPtr pcibus = NULL;
+    drmPciDeviceInfoPtr pcidevice = NULL;
+    DIR *sysdir = NULL;
+    struct dirent *dent = NULL;
+    struct stat sbuf = {0};
+    char node[PATH_MAX + 1] = "";
+    char path[PATH_MAX + 1] = "";
+    char data[128] = "";
+    char config[64] = "";
+    int node_type, subsystem_type;
+    int maj, min;
+    int fd;
+    int ret, i = 0, j, node_count, device_count = 0;
+    int max_count = 16;
+    int *duplicated = NULL;
+
+    devs = calloc(max_count, sizeof(*devs));
+    if (devs == NULL)
+        return -ENOMEM;
+
+    sysdir = opendir(DRM_DIR_NAME);
+    if (!sysdir) {
+        ret = -errno;
+        goto free_locals;
+    }
+
+    while ((dent = readdir(sysdir))) {
+        node_type = drmGetNodeType(dent->d_name);
+        if (node_type < 0)
+            continue;
+
+        snprintf(node, PATH_MAX, "%s/%s", DRM_DIR_NAME, dent->d_name);
+        if (stat(node, &sbuf))
+            continue;
+
+        maj = major(sbuf.st_rdev);
+        min = minor(sbuf.st_rdev);
+
+        if (maj != DRM_MAJOR || !S_ISCHR(sbuf.st_mode))
+            continue;
+
+        snprintf(path, PATH_MAX, "/sys/dev/char/%d:%d/device/subsystem",
+                 maj, min);
+        subsystem_type = drmParseSubsystemType(path);
+
+        if (subsystem_type < 0)
+            continue;
+
+        switch (subsystem_type) {
+        case DRM_BUS_PCI:
+            pcibus = calloc(1, sizeof(*pcibus));
+            if (pcibus == NULL) {
+                ret = -ENOMEM;
+                goto free_locals;
+            }
+
+            snprintf(path, PATH_MAX, "/sys/dev/char/%d:%d/device/uevent",
+                     maj, min);
+            fd = open(path, O_RDONLY);
+            if (fd < 0) {
+                ret = -errno;
+                goto free_locals;
+            }
+            ret = read(fd, data, sizeof(data));
+            if (ret < 0) {
+                ret = -errno;
+                close(fd);
+                goto free_locals;
+            }
+
+            ret = drmParsePciBusInfo(data, pcibus);
+            close(fd);
+            if (ret)
+                goto free_locals;
+
+            if (i >= max_count) {
+                max_count += 16;
+                devs = realloc(devs, max_count * sizeof(*devs));
+            }
+
+            devs[i].businfo.pci = pcibus;
+            devs[i].bustype = subsystem_type;
+            devs[i].nodes = calloc(DRM_NODE_MAX, sizeof(char *));
+            if (devs[i].nodes == NULL) {
+                ret = -ENOMEM;
+                goto free_locals;
+            }
+            devs[i].nodes[node_type] = strdup(node);
+            if (devs[i].nodes[node_type] == NULL) {
+                ret = -ENOMEM;
+                goto free_locals;
+            }
+            devs[i].available_nodes = 1 << node_type;
+
+            if (devices != NULL) {
+                snprintf(path, PATH_MAX, "/sys/class/drm/%s/device/config",
+                         dent->d_name);
+                fd = open(path, O_RDONLY);
+                if (fd < 0) {
+                     ret = -errno;
+                     goto free_locals;
+                }
+                ret = read(fd, config, 64);
+                if (ret < 0) {
+                    ret = -errno;
+                    close(fd);
+                    goto free_locals;
+                }
+
+                pcidevice = calloc(1, sizeof(*pcidevice));
+                if (pcidevice == NULL) {
+                    ret = -ENOMEM;
+                    goto free_locals;
+                }
+
+                ret = drmParsePciDeviceInfo(config, pcidevice);
+                if (ret)
+                    goto free_locals;
+
+                devs[i].deviceinfo.pci = pcidevice;
+                close(fd);
+            }
+            break;
+        default:
+            fprintf(stderr, "The subsystem type is not supported yet\n");
+            break;
+        }
+        i++;
+    }
+
+    node_count = i;
+
+    /* merge duplicated devices with same domain/bus/device/func IDs */
+    duplicated = calloc(node_count, sizeof(*duplicated));
+    if (duplicated == NULL) {
+        ret = -ENOMEM;
+        goto free_locals;
+    }
+
+    for (i = 0; i < node_count; i++) {
+        for (j = i+1; j < node_count; j++) {
+            if (duplicated[i] || duplicated[j])
+                continue;
+            if (drmSameDevice(&devs[i], &devs[j])) {
+                duplicated[j] = 1;
+                devs[i].available_nodes |= devs[j].available_nodes;
+                node_type = log2(devs[j].available_nodes);
+                devs[i].nodes[node_type] = devs[j].nodes[node_type];
+                free(devs[j].nodes);
+                free(devs[j].businfo.pci);
+                free(devs[j].deviceinfo.pci);
+            }
+        }
+    }
+
+    for (i = 0; i < node_count; i++) {
+        if(duplicated[i] == 0) {
+            if ((devices != NULL) && (device_count < max_devices)) {
+                devices[device_count] = calloc(1, sizeof(drmDevice));
+                if (devices[device_count] == NULL) {
+                    ret = -ENOMEM;
+                    break;
+                }
+                memcpy(devices[device_count], &devs[i], sizeof(drmDevice));
+            } else
+                drmFreeDevice(&devs[i]);
+            device_count++;
+        }
+    }
+
+    if (i < node_count) {
+        drmFreeDevices(devices, device_count);
+        for ( ; i < node_count; i++)
+            if(duplicated[i] == 0)
+                drmFreeDevice(&devs[i]);
+    } else
+        ret = device_count;
+
+    free(duplicated);
+    free(devs);
+    closedir(sysdir);
+    return ret;
+
+free_locals:
+    for (j = 0; j < i; j++)
+        drmFreeDevice(&devs[j]);
+    free(pcidevice);
+    free(pcibus);
+    free(devs);
+    closedir(sysdir);
+    return ret;
+}
+#else
+void drmFreeDevices(drmDevicePtr devices[], int count)
+{
+    (void)devices;
+    (void)count;
+}
+
+int drmGetDevices(drmDevicePtr devices[], int max_devices)
+{
+    (void)devices;
+    (void)max_devices;
+    return -EINVAL;
+}
+
+#warning "Missing implementation of drmGetDevices/drmFreeDevices"
+
+#endif
diff --git a/xf86drm.h b/xf86drm.h
index 360e04a..e82ca84 100644
--- a/xf86drm.h
+++ b/xf86drm.h
@@ -563,6 +563,8 @@  extern int           drmOpen(const char *name, const char *busid);
 #define DRM_NODE_PRIMARY 0
 #define DRM_NODE_CONTROL 1
 #define DRM_NODE_RENDER  2
+#define DRM_NODE_MAX     3
+
 extern int           drmOpenWithType(const char *name, const char *busid,
                                      int type);
 
@@ -759,6 +761,38 @@  extern int drmPrimeFDToHandle(int fd, int prime_fd, uint32_t *handle);
 extern char *drmGetPrimaryDeviceNameFromFd(int fd);
 extern char *drmGetRenderDeviceNameFromFd(int fd);
 
+#define DRM_BUS_PCI   0
+
+typedef struct _drmPciBusInfo {
+    uint16_t domain;
+    uint8_t bus;
+    uint8_t dev;
+    uint8_t func;
+} drmPciBusInfo, *drmPciBusInfoPtr;
+
+typedef struct _drmPciDeviceInfo {
+    uint16_t vendor_id;
+    uint16_t device_id;
+    uint16_t subvendor_id;
+    uint16_t subdevice_id;
+    uint8_t revision_id;
+} drmPciDeviceInfo, *drmPciDeviceInfoPtr;
+
+typedef struct _drmDevice {
+    char **nodes; /* DRM_NODE_MAX sized array */
+    int available_nodes; /* DRM_NODE_* bitmask */
+    int bustype;
+    union {
+        drmPciBusInfoPtr pci;
+    } businfo;
+    union {
+        drmPciDeviceInfoPtr pci;
+    } deviceinfo;
+} drmDevice, *drmDevicePtr;
+
+extern int drmGetDevices(drmDevicePtr devices[], int max_devices);
+extern void drmFreeDevices(drmDevicePtr devices[], int count);
+
 #if defined(__cplusplus)
 }
 #endif