Re: [PATCH 4/5] drm/xe/xe2: Limit ccs framebuffers to tile4 only

[Matthew Auld <matthew.auld@intel.com>]

On 26/01/2024 21:08, Juha-Pekka Heikkila wrote:
> Display engine support ccs only with tile4, prevent other modifiers
> from using compressed memory. Store pin time pat index to xe_bo.
> 
> Signed-off-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
> ---
>   drivers/gpu/drm/xe/display/xe_fb_pin.c | 19 +++++++++++++++++++
>   1 file changed, 19 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/display/xe_fb_pin.c b/drivers/gpu/drm/xe/display/xe_fb_pin.c
> index 722c84a56607..b2930a226f54 100644
> --- a/drivers/gpu/drm/xe/display/xe_fb_pin.c
> +++ b/drivers/gpu/drm/xe/display/xe_fb_pin.c
> @@ -10,9 +10,18 @@
>   #include "intel_fb_pin.h"
>   #include "xe_ggtt.h"
>   #include "xe_gt.h"
> +#include "xe_pat.h"
>   
>   #include <drm/ttm/ttm_bo.h>
>   
> +static bool is_compressed(const struct drm_framebuffer *fb)
> +{
> +	struct xe_bo *bo = intel_fb_obj(fb);
> +	struct xe_device *xe = to_xe_device(to_intel_framebuffer(fb)->base.dev);
> +
> +	return xe_pat_index_has_compression(xe, bo->pat_index);
> +}
> +
>   static void
>   write_dpt_rotated(struct xe_bo *bo, struct iosys_map *map, u32 *dpt_ofs, u32 bo_ofs,
>   		  u32 width, u32 height, u32 src_stride, u32 dst_stride)
> @@ -349,12 +358,22 @@ void intel_unpin_fb_vma(struct i915_vma *vma, unsigned long flags)
>   int intel_plane_pin_fb(struct intel_plane_state *plane_state)
>   {
>   	struct drm_framebuffer *fb = plane_state->hw.fb;
> +	struct xe_device *xe = to_xe_device(to_intel_framebuffer(fb)->base.dev);
>   	struct xe_bo *bo = intel_fb_obj(fb);
>   	struct i915_vma *vma;
>   
>   	/* We reject creating !SCANOUT fb's, so this is weird.. */
>   	drm_WARN_ON(bo->ttm.base.dev, !(bo->flags & XE_BO_SCANOUT_BIT));
>   
> +	if (GRAPHICS_VER(xe) >= 20) {
> +		if (fb->modifier != I915_FORMAT_MOD_4_TILED &&
> +		    is_compressed(fb)) {
> +			drm_warn(&xe->drm, "Cannot create ccs framebuffer with other than tile4 mofifier\n");
> +			return -EINVAL;
> +		}
> +		bo->pat_index_scanout = bo->pat_index;
> +	}

I think this needs to be moved into __xe_pin_fb_vma() after acquiring 
the object lock. Also not sure what prevents vm_bind appearing after we 
drop the lock? Do we need to prevent modifications until the end of 
_xe_unpin_fb_vma()?

> +
>   	vma = __xe_pin_fb_vma(to_intel_framebuffer(fb), &plane_state->view.gtt);
>   	if (IS_ERR(vma))
>   		return PTR_ERR(vma);