[PATCH 5.14 071/172] drm/amdgpu: check tiling flags when creating FB on GFX8-

Greg Kroah-Hartman
2021-10-04T13:33:19Z

From: Simon Ser <contact@emersion.fr>

commit 98122e63a7ecc08c4172a17d97a06ef5536eb268 upstream.

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)

[1]: https://github.com/swaywm/wlroots/issues/3185

Signed-off-by: Simon Ser <contact@emersion.fr>
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>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_display.c | 31 ++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)

--- 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_modif
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(stru
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(stru
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);