mbox series

[SRU,H,0/1] Fix no external DP output on some monitors

Message ID 20210817061851.6258-1-aaron.ma@canonical.com
Headers show
Series Fix no external DP output on some monitors | expand

Message

Aaron Ma Aug. 17, 2021, 6:18 a.m. UTC 
BugLink: https://bugs.launchpad.net/bugs/1938999

[Impact]
External displays not working on Thinkpad T490 with ThinkPad Thunderbolt
3 Dock

[Fix]
Some SKL systems DP output fails when AUX timeout of LTTPR detection.
Disable the LTTPR detection until GLK to fix the link training.

[Test]
Verified on hardware, external DP work fine.

[Where problems could occur]
It may break output of external DP.

This patch from 5.12-rc5, only Hirsute kernel is SRUed.

Imre Deak (1):
  drm/i915/ilk-glk: Fix link training on links with LTTPRs

 drivers/gpu/drm/i915/display/intel_dp.c           |  7 +++++++
 .../gpu/drm/i915/display/intel_dp_link_training.c | 15 ++++++++++++---
 2 files changed, 19 insertions(+), 3 deletions(-)

Comments

Aaron Ma Aug. 17, 2021, 6:39 a.m. UTC | #1 
On 8/17/21 2:18 PM, Aaron Ma wrote:
> BugLink: https://bugs.launchpad.net/bugs/1938999
> 
> [Impact]
> External displays not working on Thinkpad T490 with ThinkPad Thunderbolt
> 3 Dock
> 
> [Fix]
> Some SKL systems DP output fails when AUX timeout of LTTPR detection.
> Disable the LTTPR detection until GLK to fix the link training.
> 
> [Test]
> Verified on hardware, external DP work fine.

Also tested on I+N GPU laptop and a iGPU only laptop, all displays with dock are good.

Aaron

> 
> [Where problems could occur]
> It may break output of external DP.
> 
> This patch from 5.12-rc5, only Hirsute kernel is SRUed.
> 
> Imre Deak (1):
>    drm/i915/ilk-glk: Fix link training on links with LTTPRs
> 
>   drivers/gpu/drm/i915/display/intel_dp.c           |  7 +++++++
>   .../gpu/drm/i915/display/intel_dp_link_training.c | 15 ++++++++++++---
>   2 files changed, 19 insertions(+), 3 deletions(-)
>
Kleber Sacilotto de Souza Aug. 31, 2021, 1:28 p.m. UTC | #2 
On 17.08.21 08:18, Aaron Ma wrote:
> BugLink: https://bugs.launchpad.net/bugs/1938999
> 
> [Impact]
> External displays not working on Thinkpad T490 with ThinkPad Thunderbolt
> 3 Dock
> 
> [Fix]
> Some SKL systems DP output fails when AUX timeout of LTTPR detection.
> Disable the LTTPR detection until GLK to fix the link training.
> 
> [Test]
> Verified on hardware, external DP work fine.
> 
> [Where problems could occur]
> It may break output of external DP.
> 
> This patch from 5.12-rc5, only Hirsute kernel is SRUed.
> 
> Imre Deak (1):
>    drm/i915/ilk-glk: Fix link training on links with LTTPRs
> 
>   drivers/gpu/drm/i915/display/intel_dp.c           |  7 +++++++
>   .../gpu/drm/i915/display/intel_dp_link_training.c | 15 ++++++++++++---
>   2 files changed, 19 insertions(+), 3 deletions(-)
> 

Applied to hirsute:linux.

Thanks,
Kleber