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

[Juha-Pekka Heikkila <juhapekka.heikkila@xxxxxxxxx>]

On 29.1.2024 14.02, Matthew Auld wrote:
> 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@xxxxxxxxx>
> > ---
> >   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()?

I did now put in __xe_unpin_fb_vma()
..
vma->bo->has_sealed_pat_index = false;
..

as well as moved this above block to correct place.

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