drm/amdgpu: fix vblank_time when displays are off

commit beb3777682d5c296cc15a2a424f5a7a98476def0 upstream.

If the displays are off, set the vblank time to max to make
sure mclk switching is enabled.  Avoid mclk getting set
to high when no displays are attached.

bug: https://bugs.freedesktop.org/show_bug.cgi?id=101528
fixes: 09be4a5219 (drm/amd/powerplay/smu7: add vblank check for mclk switching (v2))
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cgs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cgs.c
index c6dba1eaefbd463a2330386ae41773a659139051..8b8eda7d1703dd2e2955a34e2df12c43f2052dfd 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cgs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cgs.c
@@ -838,6 +838,9 @@ static int amdgpu_cgs_get_active_displays_info(struct cgs_device *cgs_device,
                return -EINVAL;
 
        mode_info = info->mode_info;
+       if (mode_info)
+               /* if the displays are off, vblank time is max */
+               mode_info->vblank_time_us = 0xffffffff;
 
        if (adev->mode_info.num_crtc && adev->mode_info.mode_config_initialized) {
                list_for_each_entry(crtc,