From b9699dd862760e642807a2bc226e4d127e35dcb7 Mon Sep 17 00:00:00 2001 From: Dmitry Baryshkov Date: Tue, 17 Mar 2026 17:30:05 +0200 Subject: [PATCH] drm/msm/dpu: don't try using 2 LMs if only one DSC is available Current topology code will try using 2 LMs with just one DSC, which breaks cases like SC7280 / Fairphone5. Forbid using 2 LMs split in such a case. Fixes: 1ce69c265a53 ("drm/msm/dpu: move resource allocation to CRTC") Reported-by: Luca Weiss Closes: https://lore.kernel.org/r/DH1IKLU0YZYU.2SW4WYO7H3H4R@fairphone.com/ Tested-by: Luca Weiss # qcm6490-fairphone-fp5 Patchwork: https://patchwork.freedesktop.org/patch/712386/ Link: https://lore.kernel.org/r/20260317-fix-3d-dsc-v1-1-88b54f62f659@oss.qualcomm.com Signed-off-by: Dmitry Baryshkov --- drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c index 97aca969337f..103cdbb38968 100644 --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c @@ -1406,7 +1406,8 @@ static struct msm_display_topology dpu_crtc_get_topology( topology.num_lm = 2; else if (topology.num_dsc == 2) topology.num_lm = 2; - else if (dpu_kms->catalog->caps->has_3d_merge) + else if (dpu_kms->catalog->caps->has_3d_merge && + topology.num_dsc == 0) topology.num_lm = (mode->hdisplay > MAX_HDISPLAY_SPLIT) ? 2 : 1; else topology.num_lm = 1;