From dd4f3ee535b3b0ac027f75dbf9dc5fc88733c765 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Timur=20Krist=C3=B3f?= Date: Tue, 19 May 2026 10:41:54 +0200 Subject: [PATCH] drm/amd/pm/si: Disregard vblank time when no displays are connected MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When no displays are connected, there is no vblank happening so the power management code shouldn't worry about it. This fixes a regression that caused the memory clock to be stuck at maximum when there were no displays connected to a SI GPU. Fixes: 9003a0746864 ("drm/amd/pm: Treat zero vblank time as too short in si_dpm (v3)") Fixes: 9d73b107a61b ("drm/amd/pm: Use pm_display_cfg in legacy DPM (v2)") Reviewed-by: Alex Deucher Tested-by: Jeremy Klarenbeek Signed-off-by: Timur Kristóf Signed-off-by: Alex Deucher (cherry picked from commit 6d87e0199f7b83735b56e422d59f170a201897a8) Cc: stable@vger.kernel.org --- drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.c b/drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.c index 36942467d4ad..c3aff5d0c53d 100644 --- a/drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.c +++ b/drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.c @@ -3076,6 +3076,10 @@ static bool si_dpm_vblank_too_short(void *handle) /* we never hit the non-gddr5 limit so disable it */ u32 switch_limit = adev->gmc.vram_type == AMDGPU_VRAM_TYPE_GDDR5 ? 450 : 0; + /* Disregard vblank time when there are no displays connected */ + if (!adev->pm.pm_display_cfg.num_display) + return false; + /* Consider zero vblank time too short and disable MCLK switching. * Note that the vblank time is set to maximum when no displays are attached, * so we'll still enable MCLK switching in that case.