[2/2] drm: Return -ENOTSUPP when called for KMS cap with a non-KMS driver
diff mbox

Message ID 20161130083002.1520-2-michel@daenzer.net
State New
Headers show

Commit Message

Michel Dänzer Nov. 30, 2016, 8:30 a.m. UTC
From: Michel Dänzer <michel.daenzer@amd.com>

This is an attempt to make the previous fix a bit more robust going
forward.

Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
---
 drivers/gpu/drm/drm_ioctl.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

Comments

Daniel Vetter Nov. 30, 2016, 9:07 a.m. UTC | #1
On Wed, Nov 30, 2016 at 05:30:02PM +0900, Michel Dänzer wrote:
> From: Michel Dänzer <michel.daenzer@amd.com>
> 
> This is an attempt to make the previous fix a bit more robust going
> forward.
> 
> Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
> ---
>  drivers/gpu/drm/drm_ioctl.c | 23 +++++++++++++++++------
>  1 file changed, 17 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
> index 71c3473..32f484b 100644
> --- a/drivers/gpu/drm/drm_ioctl.c
> +++ b/drivers/gpu/drm/drm_ioctl.c
> @@ -229,6 +229,19 @@ static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_
>  	struct drm_crtc *crtc;
>  
>  	req->value = 0;
> +
> +	/* Only allow non-KMS caps with non-KMS drivers */
> +	switch (req->capability) {
> +	case DRM_CAP_DUMB_BUFFER:

Dumb buffers are only meant to be used for kms drivers, should be
disallowed too.

> +	case DRM_CAP_VBLANK_HIGH_CRTC:

Might be good to have a comment here that we need to allow this for old
ums?

> +	case DRM_CAP_PRIME:
> +	case DRM_CAP_TIMESTAMP_MONOTONIC:

This is pretty new, I don't think any of the old ums drivers was ever
updated to use it. Should probably disallow it too.
> +		break;
> +	default:
> +		if (!drm_core_check_feature(dev, DRIVER_MODESET))
> +			return -ENOTSUPP;
> +	}

And one code org bikeshed: I don't like the duplicated switch, could we
instead split it it into two disjoint sets like this?

	switch (req->capability) {
	case DRM_CAP_PRIME:
		req->value |= dev->driver->prime_fd_to_handle ? DRM_PRIME_CAP_IMPORT : 0;
		req->value |= dev->driver->prime_handle_to_fd ? DRM_PRIME_CAP_EXPORT : 0;
		break;
	... all other non-modeset caps ...
	}

	if (!drm_core_check_feature(dev, DRIVER_MODESET))
		return -ENOTSUPP;

	switch (req->capability) {
	... handle remaining caps needed for DRIVER_MODSET ...
	default:
		return -EINVAL;
	}

That way it would be a bit more obvious that people who add a new cap need
to make a decision where to put it (and by default put it in the bottom
pile).
-Daniel

>  	switch (req->capability) {
>  	case DRM_CAP_DUMB_BUFFER:
>  		if (dev->driver->dumb_create)
> @@ -254,12 +267,10 @@ static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_
>  		req->value = dev->mode_config.async_page_flip;
>  		break;
>  	case DRM_CAP_PAGE_FLIP_TARGET:
> -		if (drm_core_check_feature(dev, DRIVER_MODESET)) {
> -			req->value = 1;
> -			drm_for_each_crtc(crtc, dev) {
> -				if (!crtc->funcs->page_flip_target)
> -					req->value = 0;
> -			}
> +		req->value = 1;
> +		drm_for_each_crtc(crtc, dev) {
> +			if (!crtc->funcs->page_flip_target)
> +				req->value = 0;
>  		}
>  		break;
>  	case DRM_CAP_CURSOR_WIDTH:
> -- 
> 2.10.2
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
Alex Deucher Nov. 30, 2016, 5:21 p.m. UTC | #2
On Wed, Nov 30, 2016 at 4:07 AM, Daniel Vetter <daniel@ffwll.ch> wrote:
> On Wed, Nov 30, 2016 at 05:30:02PM +0900, Michel Dänzer wrote:
>> From: Michel Dänzer <michel.daenzer@amd.com>
>>
>> This is an attempt to make the previous fix a bit more robust going
>> forward.
>>
>> Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
>> ---
>>  drivers/gpu/drm/drm_ioctl.c | 23 +++++++++++++++++------
>>  1 file changed, 17 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
>> index 71c3473..32f484b 100644
>> --- a/drivers/gpu/drm/drm_ioctl.c
>> +++ b/drivers/gpu/drm/drm_ioctl.c
>> @@ -229,6 +229,19 @@ static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_
>>       struct drm_crtc *crtc;
>>
>>       req->value = 0;
>> +
>> +     /* Only allow non-KMS caps with non-KMS drivers */
>> +     switch (req->capability) {
>> +     case DRM_CAP_DUMB_BUFFER:
>
> Dumb buffers are only meant to be used for kms drivers, should be
> disallowed too.
>
>> +     case DRM_CAP_VBLANK_HIGH_CRTC:
>
> Might be good to have a comment here that we need to allow this for old
> ums?
>

I don't think we need this for UMS.  It was added for evergreen and we
only supported this feature on KMS.

Alex

>> +     case DRM_CAP_PRIME:
>> +     case DRM_CAP_TIMESTAMP_MONOTONIC:
>
> This is pretty new, I don't think any of the old ums drivers was ever
> updated to use it. Should probably disallow it too.
>> +             break;
>> +     default:
>> +             if (!drm_core_check_feature(dev, DRIVER_MODESET))
>> +                     return -ENOTSUPP;
>> +     }
>
> And one code org bikeshed: I don't like the duplicated switch, could we
> instead split it it into two disjoint sets like this?
>
>         switch (req->capability) {
>         case DRM_CAP_PRIME:
>                 req->value |= dev->driver->prime_fd_to_handle ? DRM_PRIME_CAP_IMPORT : 0;
>                 req->value |= dev->driver->prime_handle_to_fd ? DRM_PRIME_CAP_EXPORT : 0;
>                 break;
>         ... all other non-modeset caps ...
>         }
>
>         if (!drm_core_check_feature(dev, DRIVER_MODESET))
>                 return -ENOTSUPP;
>
>         switch (req->capability) {
>         ... handle remaining caps needed for DRIVER_MODSET ...
>         default:
>                 return -EINVAL;
>         }
>
> That way it would be a bit more obvious that people who add a new cap need
> to make a decision where to put it (and by default put it in the bottom
> pile).
> -Daniel
>
>>       switch (req->capability) {
>>       case DRM_CAP_DUMB_BUFFER:
>>               if (dev->driver->dumb_create)
>> @@ -254,12 +267,10 @@ static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_
>>               req->value = dev->mode_config.async_page_flip;
>>               break;
>>       case DRM_CAP_PAGE_FLIP_TARGET:
>> -             if (drm_core_check_feature(dev, DRIVER_MODESET)) {
>> -                     req->value = 1;
>> -                     drm_for_each_crtc(crtc, dev) {
>> -                             if (!crtc->funcs->page_flip_target)
>> -                                     req->value = 0;
>> -                     }
>> +             req->value = 1;
>> +             drm_for_each_crtc(crtc, dev) {
>> +                     if (!crtc->funcs->page_flip_target)
>> +                             req->value = 0;
>>               }
>>               break;
>>       case DRM_CAP_CURSOR_WIDTH:
>> --
>> 2.10.2
>>
>> _______________________________________________
>> dri-devel mailing list
>> dri-devel@lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
Michel Dänzer Dec. 1, 2016, 7:35 a.m. UTC | #3
On 30/11/16 06:07 PM, Daniel Vetter wrote:
> On Wed, Nov 30, 2016 at 05:30:02PM +0900, Michel Dänzer wrote:
>> From: Michel Dänzer <michel.daenzer@amd.com>
>>
>> This is an attempt to make the previous fix a bit more robust going
>> forward.
>>
>> Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
>> ---
>>  drivers/gpu/drm/drm_ioctl.c | 23 +++++++++++++++++------
>>  1 file changed, 17 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
>> index 71c3473..32f484b 100644
>> --- a/drivers/gpu/drm/drm_ioctl.c
>> +++ b/drivers/gpu/drm/drm_ioctl.c
>> @@ -229,6 +229,19 @@ static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_
>>  	struct drm_crtc *crtc;
>>  
>>  	req->value = 0;
>> +
>> +	/* Only allow non-KMS caps with non-KMS drivers */
>> +	switch (req->capability) {
>> +	case DRM_CAP_DUMB_BUFFER:
> 
> Dumb buffers are only meant to be used for kms drivers, should be
> disallowed too.
> 
>> +	case DRM_CAP_VBLANK_HIGH_CRTC:
> 
> Might be good to have a comment here that we need to allow this for old
> ums?

This is effectively KMS-only as well, per Alex (thanks!).


>> +	case DRM_CAP_PRIME:
>> +	case DRM_CAP_TIMESTAMP_MONOTONIC:
> 
> This is pretty new, I don't think any of the old ums drivers was ever
> updated to use it. Should probably disallow it too.

DRM_CAP_TIMESTAMP_MONOTONIC is driver independent, I don't see why it
wouldn't work fine with UMS drivers. OTOH, I don't think DRM_CAP_PRIME
can work with UMS.


>> +		break;
>> +	default:
>> +		if (!drm_core_check_feature(dev, DRIVER_MODESET))
>> +			return -ENOTSUPP;
>> +	}
> 
> And one code org bikeshed: I don't like the duplicated switch, could we
> instead split it it into two disjoint sets like this?
> 
> 	switch (req->capability) {
> 	case DRM_CAP_PRIME:
> 		req->value |= dev->driver->prime_fd_to_handle ? DRM_PRIME_CAP_IMPORT : 0;
> 		req->value |= dev->driver->prime_handle_to_fd ? DRM_PRIME_CAP_EXPORT : 0;
> 		break;
> 	... all other non-modeset caps ...
> 	}
> 
> 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
> 		return -ENOTSUPP;
> 
> 	switch (req->capability) {
> 	... handle remaining caps needed for DRIVER_MODSET ...
> 	default:
> 		return -EINVAL;
> 	}
> 
> That way it would be a bit more obvious that people who add a new cap need
> to make a decision where to put it (and by default put it in the bottom
> pile).

Your pseudo-code wouldn't work correctly, but I get your idea. :)


v2 addressing review feedback coming up soon.

Patch
diff mbox

diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index 71c3473..32f484b 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -229,6 +229,19 @@  static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_
 	struct drm_crtc *crtc;
 
 	req->value = 0;
+
+	/* Only allow non-KMS caps with non-KMS drivers */
+	switch (req->capability) {
+	case DRM_CAP_DUMB_BUFFER:
+	case DRM_CAP_VBLANK_HIGH_CRTC:
+	case DRM_CAP_PRIME:
+	case DRM_CAP_TIMESTAMP_MONOTONIC:
+		break;
+	default:
+		if (!drm_core_check_feature(dev, DRIVER_MODESET))
+			return -ENOTSUPP;
+	}
+
 	switch (req->capability) {
 	case DRM_CAP_DUMB_BUFFER:
 		if (dev->driver->dumb_create)
@@ -254,12 +267,10 @@  static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_
 		req->value = dev->mode_config.async_page_flip;
 		break;
 	case DRM_CAP_PAGE_FLIP_TARGET:
-		if (drm_core_check_feature(dev, DRIVER_MODESET)) {
-			req->value = 1;
-			drm_for_each_crtc(crtc, dev) {
-				if (!crtc->funcs->page_flip_target)
-					req->value = 0;
-			}
+		req->value = 1;
+		drm_for_each_crtc(crtc, dev) {
+			if (!crtc->funcs->page_flip_target)
+				req->value = 0;
 		}
 		break;
 	case DRM_CAP_CURSOR_WIDTH: