Re: [PATCH v2] amdgpu: check tiling flags when creating FB on GFX8-

On Mon, Sep 27, 2021 at 11:09 AM Simon Ser contact@emersion.fr wrote:

On GFX9+, format modifiers are always enabled and ensure the frame-buffers can be scanned out at ADDFB2 time.

On GFX8-, format modifiers are not supported and no other check is performed. This means ADDFB2 IOCTLs will succeed even if the tiling isn't supported for scan-out, and will result in garbage displayed on screen [1].

Fix this by adding a check for tiling flags for GFX8 and older. The check is taken from radeonsi in Mesa (see how is_displayable is populated in gfx6_compute_surface).

Changes in v2: use drm_WARN_ONCE instead of drm_WARN (Michel)

Signed-off-by: Simon Ser contact@emersion.fr Cc: stable@vger.kernel.org Acked-by: Michel Dänzer mdaenzer@redhat.com Cc: Alex Deucher alexander.deucher@amd.com Cc: Harry Wentland hwentlan@amd.com Cc: Nicholas Kazlauskas Nicholas.Kazlauskas@amd.com Cc: Bas Nieuwenhuizen bas@basnieuwenhuizen.nl

Applied. Thanks.

Alex

---

drivers/gpu/drm/amd/amdgpu/amdgpu_display.c | 31 +++++++++++++++++++++ 1 file changed, 31 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c index 58bfc7f00d76..5faf3ef28080 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c @@ -837,6 +837,28 @@ static int convert_tiling_flags_to_modifier(struct amdgpu_framebuffer *afb) return 0; }

+/* Mirrors the is_displayable check in radeonsi's gfx6_compute_surface */ +static int check_tiling_flags_gfx6(struct amdgpu_framebuffer *afb) +{

•   u64 micro_tile_mode;
  

•   /* Zero swizzle mode means linear */
  

•   if (AMDGPU_TILING_GET(afb->tiling_flags, SWIZZLE_MODE) == 0)
  

•           return 0;
  

•   micro_tile_mode = AMDGPU_TILING_GET(afb->tiling_flags, MICRO_TILE_MODE);
  

•   switch (micro_tile_mode) {
  

•   case 0: /* DISPLAY */
  

•   case 3: /* RENDER */
  

•           return 0;
  

•   default:
  

•           drm_dbg_kms(afb->base.dev,
  

•                       "Micro tile mode %llu not supported for scanout\n",
  

•                       micro_tile_mode);
  

•           return -EINVAL;
  

•   }
  

+}

static void get_block_dimensions(unsigned int block_log2, unsigned int cpp, unsigned int *width, unsigned int *height) { @@ -1103,6 +1125,7 @@ int amdgpu_display_framebuffer_init(struct drm_device *dev, const struct drm_mode_fb_cmd2 *mode_cmd, struct drm_gem_object *obj) {

•   struct amdgpu_device *adev = drm_to_adev(dev);
    int ret, i;
  
    /*
  

@@ -1122,6 +1145,14 @@ int amdgpu_display_framebuffer_init(struct drm_device *dev, if (ret) return ret;

•   if (!dev->mode_config.allow_fb_modifiers) {
  

•           drm_WARN_ONCE(dev, adev->family >= AMDGPU_FAMILY_AI,
  

•                         "GFX9+ requires FB check based on format modifier\n");
  

•           ret = check_tiling_flags_gfx6(rfb);
  

•           if (ret)
  

•                   return ret;
  

•   }
  

•   if (dev->mode_config.allow_fb_modifiers &&
        !(rfb->base.flags & DRM_MODE_FB_MODIFIERS)) {
            ret = convert_tiling_flags_to_modifier(rfb);
  

-- 2.33.0