APPLIED (unstable/5.11): [PATCH 0/1][Unstable/OEM-5.10] UBUNTU: SAUCE: Fix the video can't output through WD19TB connected with TGL platform during cold-boot

[Andrea Righi]

On Tue, Jan 05, 2021 at 05:33:46PM +0800, Koba Ko wrote:
> BugLink: https://bugs.launchpad.net/bugs/1910211
> 
> [Impact]
> After Apply the patches from https://www.spinics.net/lists/intel-gfx/msg248700.html, 
> the TGL platform would have the failure rate(1/20) on outputting the video through WD19TB.
> 
> [Fix]
> The patch is provided by Imre(https://gitlab.freedesktop.org/drm/intel/-/issues/2801#note_740352).
> If there's no lttpr in the link chain, the DRM driver wouldn't configure the transparent mode again.
> 
> [Test Case]
> 1. Connected the WD19TB with the TGL platform and
> connected the external monitor on WD19TB with HDMI/Displayport.
> 2. Don't plug the external monitor on the TGL platform, so there's only one monitor on WD19TB.
> 3. Cold boot the TGL platform.
> 4. Check the monitor can be blinked and the video can output to the monitor.
> 
> [Where problems could occur]
> As per Imre's comment, this may be caused by the dock.
> In the future if the WD19TB's firmware is updated, we may encounter the same issue again.
> 
> 
> Imre Deak (1):
>   UBUNTU: SAUCE: drm/i915/dp: Prevent setting LTTPR mode if no LTTPR is
>     detected

Applied to unstable/5.11.

Thanks,
-Andrea