[PATCH 1/5] drm/amd/pm/si: Disregard vblank time when no displays are connected

["Timur Kristóf" <timur.kristof@gmail.com>]

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)")
Tested-by: Jeremy Klarenbeek <jeremy.klarenbeek99@gmail.com>
Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
---
 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 b75a6031c68a..5afe42918497 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.
-- 
2.54.0