NACK[U]: [PATCH 0/1][SRU][L/M/U] Fix eDP only displays 3/4 area after switching to mirror mode with external HDMI 4K monitor

[Andrea Righi]

On Wed, Jul 19, 2023 at 09:11:24PM +0800, Chris Chiu wrote:
> BugLink: https://bugs.launchpad.net/bugs/2024273
> 
> [Impact]
> Panel on laptops connect to some 4K monitors via HDMI only display 3/4 area on eDP after switching to mirror mode.
> 
> [Fix]
> Backport a fix from Intel on https://cgit.freedesktop.org/drm-tip/commit/?id=a2da67028cd05516343533c1609fcaf037237fed.
> 
> [Test]
> 1. Power on the laptop
> 2. Connect a 4K monitor (4k Benq EL2870U, 4k HP z27Kg3, 2k ASUS PA27AC) to the laptop with HDMI cable.
> 3. Switch to mirror mode from default Joint Mode
> 4. Verify there's no obvious blank space on the leftmost/rightmost side of the laptop's panel.
> 
> [Where problems could occur]
> Only observed after connecting with some particular 4K monitors. It's a generic fix to accept arbitrary refresh rate for more advanced panels. Should be low risk to old machines.

Already applied to linux-unstable via periodic upstream rebase.

-Andrea