The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 9882a40640036d5bbc590426a78981526d4f2345 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025110838-imply-extruding-3561@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 9882a40640036d5bbc590426a78981526d4f2345 Mon Sep 17 00:00:00 2001 From: Ariel D'Alessandro ariel.dalessandro@collabora.com Date: Fri, 24 Oct 2025 17:27:56 -0300 Subject: [PATCH] drm/mediatek: Disable AFBC support on Mediatek DRM driver

Commit c410fa9b07c3 ("drm/mediatek: Add AFBC support to Mediatek DRM driver") added AFBC support to Mediatek DRM and enabled the 32x8/split/sparse modifier.

However, this is currently broken on Mediatek MT8188 (Genio 700 EVK platform); tested using upstream Kernel and Mesa (v25.2.1), AFBC is used by default since Mesa v25.0.

Kernel trace reports vblank timeouts constantly, and the render is garbled:

``` [CRTC:62:crtc-0] vblank wait timed out WARNING: CPU: 7 PID: 70 at drivers/gpu/drm/drm_atomic_helper.c:1835 drm_atomic_helper_wait_for_vblanks.part.0+0x24c/0x27c [...] Hardware name: MediaTek Genio-700 EVK (DT) Workqueue: events_unbound commit_work pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : drm_atomic_helper_wait_for_vblanks.part.0+0x24c/0x27c lr : drm_atomic_helper_wait_for_vblanks.part.0+0x24c/0x27c sp : ffff80008337bca0 x29: ffff80008337bcd0 x28: 0000000000000061 x27: 0000000000000000 x26: 0000000000000001 x25: 0000000000000000 x24: ffff0000c9dcc000 x23: 0000000000000001 x22: 0000000000000000 x21: ffff0000c66f2f80 x20: ffff0000c0d7d880 x19: 0000000000000000 x18: 000000000000000a x17: 000000040044ffff x16: 005000f2b5503510 x15: 0000000000000000 x14: 0000000000000000 x13: 74756f2064656d69 x12: 742074696177206b x11: 0000000000000058 x10: 0000000000000018 x9 : ffff800082396a70 x8 : 0000000000057fa8 x7 : 0000000000000cce x6 : ffff8000823eea70 x5 : ffff0001fef5f408 x4 : ffff80017ccee000 x3 : ffff0000c12cb480 x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0000c12cb480 Call trace: drm_atomic_helper_wait_for_vblanks.part.0+0x24c/0x27c (P) drm_atomic_helper_commit_tail_rpm+0x64/0x80 commit_tail+0xa4/0x1a4 commit_work+0x14/0x20 process_one_work+0x150/0x290 worker_thread+0x2d0/0x3ec kthread+0x12c/0x210 ret_from_fork+0x10/0x20 ---[ end trace 0000000000000000 ]--- ```

Until this gets fixed upstream, disable AFBC support on this platform, as it's currently broken with upstream Mesa.

Fixes: c410fa9b07c3 ("drm/mediatek: Add AFBC support to Mediatek DRM driver") Cc: stable@vger.kernel.org Signed-off-by: Ariel D'Alessandro ariel.dalessandro@collabora.com Reviewed-by: Daniel Stone daniels@collabora.com Reviewed-by: CK Hu ck.hu@mediatek.com Reviewed-by: Macpaul Lin macpaul.lin@mediatek.com Link: https://patchwork.kernel.org/project/dri-devel/patch/20251024202756.811425-1... Signed-off-by: Chun-Kuang Hu chunkuang.hu@kernel.org

diff --git a/drivers/gpu/drm/mediatek/mtk_plane.c b/drivers/gpu/drm/mediatek/mtk_plane.c index 02349bd44001..788b52c1d10c 100644 --- a/drivers/gpu/drm/mediatek/mtk_plane.c +++ b/drivers/gpu/drm/mediatek/mtk_plane.c @@ -21,9 +21,6 @@

static const u64 modifiers[] = { DRM_FORMAT_MOD_LINEAR, - DRM_FORMAT_MOD_ARM_AFBC(AFBC_FORMAT_MOD_BLOCK_SIZE_32x8 | - AFBC_FORMAT_MOD_SPLIT | - AFBC_FORMAT_MOD_SPARSE), DRM_FORMAT_MOD_INVALID, };

@@ -71,26 +68,7 @@ static bool mtk_plane_format_mod_supported(struct drm_plane *plane, uint32_t format, uint64_t modifier) { - if (modifier == DRM_FORMAT_MOD_LINEAR) - return true; - - if (modifier != DRM_FORMAT_MOD_ARM_AFBC( - AFBC_FORMAT_MOD_BLOCK_SIZE_32x8 | - AFBC_FORMAT_MOD_SPLIT | - AFBC_FORMAT_MOD_SPARSE)) - return false; - - if (format != DRM_FORMAT_XRGB8888 && - format != DRM_FORMAT_ARGB8888 && - format != DRM_FORMAT_BGRX8888 && - format != DRM_FORMAT_BGRA8888 && - format != DRM_FORMAT_ABGR8888 && - format != DRM_FORMAT_XBGR8888 && - format != DRM_FORMAT_RGB888 && - format != DRM_FORMAT_BGR888) - return false; - - return true; + return modifier == DRM_FORMAT_MOD_LINEAR; }

static void mtk_plane_destroy_state(struct drm_plane *plane,