[Intel-gfx] [PATCH 1/2] drm/i915/skl: Allow universal planes to position

[Tvrtko Ursulin]

On 10/04/15 10:07, Sonika Jindal wrote:
> Signed-off-by: Sonika Jindal <sonika.jindal at intel.com>
> Reviewed-by: Matt Roper <matthew.d.roper at intel.com>
> ---
>   drivers/gpu/drm/i915/intel_display.c |    7 ++++++-
>   1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index ceb2e61..f0bbc22 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -12150,16 +12150,21 @@ intel_check_primary_plane(struct drm_plane *plane,
>   	struct drm_rect *dest = &state->dst;
>   	struct drm_rect *src = &state->src;
>   	const struct drm_rect *clip = &state->clip;
> +	bool can_position = false;
>   	int ret;
>
>   	crtc = crtc ? crtc : plane->crtc;
>   	intel_crtc = to_intel_crtc(crtc);
>
> +	if (INTEL_INFO(dev)->gen >= 9)
> +		can_position = true;
> +
>   	ret = drm_plane_helper_check_update(plane, crtc, fb,
>   					    src, dest, clip,
>   					    DRM_PLANE_HELPER_NO_SCALING,
>   					    DRM_PLANE_HELPER_NO_SCALING,
> -					    false, true, &state->visible);
> +					    can_position, true,
> +					    &state->visible);
>   	if (ret)
>   		return ret;
>
>

I have discovered today that, while this allows SetCrtc and SetPlane 
ioctls to work with frame buffers which do not cover the plane, page 
flips are not that lucky and fail roughly with:

[drm:drm_crtc_check_viewport] Invalid fb size 1080x1080 for CRTC 
viewport 1920x1080+0+0.

I have posted a quick IGT exerciser for this as "kms_rotation_crc: 
Excercise page flips with 90 degree rotation". May not be that great but 
shows the failure.

I am not that hot on meddling with this code, nor do I feel competent to 
even try on my own at least. :/ Maybe just because the atomic and plane 
related rewrites have been going on for so long, and have multiple 
people involved, it all sounds pretty scary and fragile.

But I think some sort of plan on how to fix this could be in order?

Regards,

Tvrtko