Xorg display issues with 4.12.{0,2}

[Ludovic Courtès]

Hello,

With 4.12.0 and 4.12.2, I have display issues with Xorg on my external
screen (display on the laptop’s screen is fine): everything gets
displayed very slowly.  With kernels up to 4.11.6 things were fine.
That’s with an Intel graphics card.

Has anybody experienced something similar?

Thanks,
Ludo’.