[PATCH 0/2 V2][SRU][U/J/OEM-5.14/OEM-5.17] UBUNTU: SAUCE: Fix WD22TB4 suspend and resume, two external monitor can not output

[Koba Ko]

On Tue, Jun 21, 2022 at 10:00 PM Tim Gardner <tim.gardner at canonical.com> wrote:
>
> On 6/20/22 23:33, Koba Ko wrote:
> > BugLink: https://bugs.launchpad.net/bugs/1979267
> >
> > [Impact]
> > Resume SUT from suspend mode, found external monitors can not output, but display setting can recognize external monitors.
> >
> > [Fix]
> > The WD22TB4 Thunderbolt dock at least will revert its DP_MAX_LINK_RATE
> > from HBR3 to HBR2 after system suspend/resume if the DP_DP13_DPCD_REV
> > registers are not read subsequently also as required.
> >
> > Fix this by reading DP_DP13_DPCD_REV registers as well, matching what is
> > done during connector detection. While at it also fix up the same call
> > in drm_dp_mst_dump_topology().
> >
> > [Test Case]
> > 1. Connect two 4K external monitor to WD22TB4.
> > 2. Put SUT into suspend mode and wait 30sec
> > 3. Resume SUT from suspend mode, found external monitors can not output.
> >
> > [Where problems could occur]
> > low
> >
> > V2: Add "UBUNTU: SAUCE:"
> >
> > Imre Deak (1):
> >    drm/dp/mst: Read the extended DPCD capabilities during system resume
> >
> >   drivers/gpu/drm/drm_dp_mst_topology.c | 7 ++-----
> >   1 file changed, 2 insertions(+), 5 deletions(-)
> >
>
> For Jammy/linux I think we ought to wait until these patches are at
> least merged to linux-next.
It has landed on linux-next
7a710a8bc909313951eb9252d8419924c771d7c2) drm/dp/mst: Read the
extended DPCD capabilities during system resume

Should I re-SRU?

>
> rtg
>
> --
> -----------
> Tim Gardner
> Canonical, Inc