| Message ID | 20181211220401.58775-1-ftigeot@wolfpond.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [libdrm] libdrm: Fix drmNodeIsDRM() on DragonFly | expand |
On Tue, 11 Dec 2018 at 22:15, François Tigeot <ftigeot@wolfpond.org> wrote: > > * There is no way to check if a device name is really a drm device > by looking it up in a virtual filesystem like on Linux > > * The major device number is also dynamically allocated from a pool, > comparing it to a constant makes no sense > > * In the absence of better ideas, just assume the device name really > points to a drm device and always return true > I guess one could use the sysfs path, although that may require a few extra lines to the linux emulation layer. What's the reason behind the dynamic allocation of the major? FWIW some userspace requires a fixed DRM_MAJOR - they will need patching to run :-( Thanks Emil
On Mon, Dec 17, 2018 at 06:09:47PM +0000, Emil Velikov wrote: > On Tue, 11 Dec 2018 at 22:15, François Tigeot <ftigeot@wolfpond.org> wrote: > > > > * There is no way to check if a device name is really a drm device > > by looking it up in a virtual filesystem like on Linux > > > > * The major device number is also dynamically allocated from a pool, > > comparing it to a constant makes no sense > > > > * In the absence of better ideas, just assume the device name really > > points to a drm device and always return true > > > I guess one could use the sysfs path, although that may require a few > extra lines to the linux emulation layer. We currently have such a thing living in local patches and it's a source of pain; it regularly breaks for one reason or another. It's not using sysfs but a hw.dri sysctl mechanism originating from FreeBSD. Some of the patches are visible here: https://github.com/DragonFlyBSD/DPorts/blob/master/graphics/libdrm/files/patch-xf86drm.c > What's the reason behind the dynamic allocation of the major? FWIW > some userspace requires a fixed DRM_MAJOR - they will need patching to > run :-( Major/minor numbers were required when device files had to be created on regular filesystem like UFS but when a devfs filesystem was implemented for DragonFly almost a decade ago, nobody thought it was important anymore. There have been no fixed major numbers on DragonFly since 2009 or so.
On Tuesday, 2018-12-18 20:11:27 +0100, Francois Tigeot wrote: > On Mon, Dec 17, 2018 at 06:09:47PM +0000, Emil Velikov wrote: > > On Tue, 11 Dec 2018 at 22:15, François Tigeot <ftigeot@wolfpond.org> wrote: > > > > > > * There is no way to check if a device name is really a drm device > > > by looking it up in a virtual filesystem like on Linux > > > > > > * The major device number is also dynamically allocated from a pool, > > > comparing it to a constant makes no sense > > > > > > * In the absence of better ideas, just assume the device name really > > > points to a drm device and always return true > > > > > I guess one could use the sysfs path, although that may require a few > > extra lines to the linux emulation layer. > > We currently have such a thing living in local patches and it's a source > of pain; it regularly breaks for one reason or another. > It's not using sysfs but a hw.dri sysctl mechanism originating from FreeBSD. > Some of the patches are visible here: > https://github.com/DragonFlyBSD/DPorts/blob/master/graphics/libdrm/files/patch-xf86drm.c I'm going through those right now, and I'll send patches for those that make sense upstream. Apologies in advance for the rebase pains :] > > > What's the reason behind the dynamic allocation of the major? FWIW > > some userspace requires a fixed DRM_MAJOR - they will need patching to > > run :-( > > Major/minor numbers were required when device files had to be created on > regular filesystem like UFS but when a devfs filesystem was implemented > for DragonFly almost a decade ago, nobody thought it was important anymore. > > There have been no fixed major numbers on DragonFly since 2009 or so. Fwiw, this `if dragonfly return true` patch is: Acked-by: Eric Engestrom <eric.engestrom@intel.com>
diff --git a/xf86drm.c b/xf86drm.c index 71ad54ba..0085bf17 100644 --- a/xf86drm.c +++ b/xf86drm.c @@ -2778,6 +2778,8 @@ static bool drmNodeIsDRM(int maj, int min) snprintf(path, sizeof(path), "/sys/dev/char/%d:%d/device/drm", maj, min); return stat(path, &sbuf) == 0; +#elif __DragonFly__ + return true; /* DragonFly BSD has no fixed major device numbers */ #else return maj == DRM_MAJOR; #endif
* There is no way to check if a device name is really a drm device by looking it up in a virtual filesystem like on Linux * The major device number is also dynamically allocated from a pool, comparing it to a constant makes no sense * In the absence of better ideas, just assume the device name really points to a drm device and always return true Signed-off-by: François Tigeot <ftigeot@wolfpond.org> --- xf86drm.c | 2 ++ 1 file changed, 2 insertions(+)