[Intel-gfx] [PATCH] drm/i915: Add not fenceable reason to not enable FBC

[Chris Wilson]

Quoting José Roberto de Souza (2019-03-22 00:42:59)
> There is some kms_frontbuffer_tracking failures due FBC being
> disabled with the reason "framebuffer not tiled or fenced".
> Although the test is setting up everything correctly to have
> FBC enabled sporadically it is failing, due the alignment and size
> restrictions in __i915_vma_set_map_and_fenceable().
> 
> So lets add another FBC failure reason and skip tests when that is
> set and keep "framebuffer not tiled or fenced" as error as it
> indicates that buffer is not tiled due wrong setup of the test.
> 
> Also fixing close typos.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108040
> Cc: Paulo Zanoni <paulo.r.zanoni at intel.com>
> Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_fbc.c | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c
> index 656e684e7c9a..2980a3b579e0 100644
> --- a/drivers/gpu/drm/i915/intel_fbc.c
> +++ b/drivers/gpu/drm/i915/intel_fbc.c
> @@ -726,19 +726,30 @@ static bool intel_fbc_can_activate(struct intel_crtc *crtc)
>          * by the CPU to the scanout and trigger updates to the FBC.
>          *
>          * Note that is possible for a tiled surface to be unmappable (and
> -        * so have no fence associated with it) due to aperture constaints
> +        * so have no fence associated with it) due to aperture constraints
>          * at the time of pinning.
>          *
>          * FIXME with 90/270 degree rotation we should use the fence on
>          * the normal GTT view (the rotated view doesn't even have a
>          * fence). Would need changes to the FBC fence Y offset as well.
> -        * For now this will effecively disable FBC with 90/270 degree
> +        * For now this will effectively disable FBC with 90/270 degree
>          * rotation.
>          */
> +       if (!(cache->vma->flags & I915_VMA_CAN_FENCE)) {

if (!i915_vma_is_map_and_fenceable(cache->vma)) {

> +               /* Requirements not meet see __i915_vma_set_map_and_fenceable() */

I would suggest pointing at intel_pin_and_fence_fb and
i915_gem_object_pin_to_display_plane as to why it chose not to require
a fence.
-Chris