APPLIED[Unstable]/cmt: [PATCH v2 0/1][SRU][F/G/Unstable/OEM-5.6] drm/i915/dp_mst - System would hang during the boot up

[Seth Forshee]

On Wed, Nov 04, 2020 at 09:43:06AM +0800, Koba Ko wrote:
> BugLink: https://bugs.launchpad.net/bugs/1902469
> 
> [Impact]
> The machine connect with the external monitor on dock(Thunderbolt),
> Then system would hang during the boot-up.
> 
> [Fix]
> The atomic check hooks must look up the encoder to be used with a
> connector from the connector's atomic state, and not assume that it's
> the connector's current attached encoder. The latter one can change
> under the atomic check func, or can be unset yet as in the case of MST
> connectors.
> 
> [test]
> With the patch, The machine connect with the external monitor on dock(Thunderbolt),
> Then system boot up successfully.
> 
> [Regression Potential]
> Low. This patch is also verified by others and is archived in the drmtip.
> 
> V2: 
> 1. cherry-pick from linux-next.
> 2. Add Groovy and Unstable.

I had actually seen this issue with groovy, and applied a different fix
that I forgot to forward upstream. I've reverted that patch in unstable
to apply this fix, the same will need to be done with groovy.

Applied to unstable/master, thanks!