[PATCH] drm: Allow CAP_PRIME on !MODESET

[Chris Wilson]

On Wed, Dec 07, 2016 at 02:13:23PM +0100, Daniel Vetter wrote:
> vgem (and our igt tests using vgem) need this. I suspect etnaviv will
> fare similarly.
> 
> Fixes: d5264ed3823a ("drm: Return -ENOTSUPP when called for KMS cap with a non-KMS driver")
> Cc: Michel Dänzer <michel.daenzer at amd.com>
> Cc: Alex Deucher <alexander.deucher at amd.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> ---
>  drivers/gpu/drm/drm_ioctl.c | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
> index 0a900bd4575d..60bf95644739 100644
> --- a/drivers/gpu/drm/drm_ioctl.c
> +++ b/drivers/gpu/drm/drm_ioctl.c
> @@ -234,10 +234,15 @@ static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_
>  
>  	req->value = 0;
>  
> -	/* Only one cap makes sense with a UMS driver: */
> -	if (req->capability == DRM_CAP_TIMESTAMP_MONOTONIC) {
> +	/* Only some caps make sense with UMS/render-only drivers. */
> +	switch (req->capability) ) {
> +	case DRM_CAP_TIMESTAMP_MONOTONIC:
>  		req->value = drm_timestamp_monotonic;
>  		return 0;
> +	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;
> +		return 0;

Slightly changes old behaviour but shouldn't we also be checking
driver->features?

if (drm_core_check_feature(dev, DRIVER_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;
}

Paranoia says second patch as a potential change of abi. So,

Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre