[Acked] [SRU] [Bionic] [PATCH 0/1] Urgent fix for docking station

[Andy Whitcroft]

On Tue, Jan 29, 2019 at 07:36:59PM +0800, Kai-Heng Feng wrote:
> BugLink: https://bugs.launchpad.net/bugs/1813663
> 
> [Impact]
> Once -44 -generic kernel lands -updates, i915 stops working when using
> docking station's MST DP:
> [ 378.105226] BUG: unable to handle kernel NULL pointer dereference at 0000000000000245
> [ 378.105296] IP: intel_ddi_post_disable+0x54/0x170 [i915]
> 
> [Fix]
> Revert "drm/i915/dp: Send DPCD ON for MST before phy_up".
> 
> [Test]
> User confirmed reverting the commit can fix the issue.
> 
> [Regression Potential]
> Low. If this commit is important then we need to also backport its
> dependencies.
> 
> Kai-Heng Feng (1):
>   Revert "drm/i915/dp: Send DPCD ON for MST before phy_up"
> 
>  drivers/gpu/drm/i915/intel_ddi.c    | 8 ++------
>  drivers/gpu/drm/i915/intel_dp_mst.c | 5 -----
>  2 files changed, 2 insertions(+), 11 deletions(-)

New stable fix causing issues, so noone should be relying on the
reverted functionality who was not broken before.  Testing reporting
good.

Acked-by: Andy Whitcroft <apw at canonical.com>

-apw