[v2,1/2] drm/msm/dpu1: don't choke on disabling the writeback connector

[Leonard Lausen]

Dear György,

On 8/30/24 13:36, György Kurucz wrote:
> For context, I have a Lenovo Yoga Slim 7x laptop, and was having issues with the display staying black after sleep. As a workaround, I could switch to a different VT and back.

Do you observe this issue on every suspend-resume cycle? On sc7180 trogdor lazor, I do observe the same "display staying black after sleep" in some of the suspend-resume cycles. I have not been able to observe a pattern with respect to when the issue occurs and when it does not. "[drm:drm_mode_config_helper_resume] *ERROR* Failed to resume (-22)" is printed in either case. Switching to a different VT and back works to restore display functionality after those suspend-resume cycles that experience the issue.

On sc7180 lazor, I do observe that this patch deterministically breaks restoring the CRTC state and functionality after resume. Can you please validate if you observe the same on Lenovo Yoga Slim 7x? Specifically, try set Night Light in your desktop environment to "Always On" and observe whether the screen remains in "Night Light" mode after resume. For lazor, "Night Light" is breaks after applying this patch and even manually toggling it off and on after resume does not restore "Night Light" / CRTC functionality.

Best regards
Leonard