Comment 47 for bug 1615871

(In reply to Leho Kraav (:macmaN :lkraav) from comment #29)
> I think I bumped into this today. Running gentoo and this package set:
>
> x11-drivers/xf86-video-intel-2.99.917_p20160218 USE="dri3 uxa" (so GLAMOR,
> not SNA)
> media-libs/mesa-11.0.6 USE=dri3
> www-client/google-chrome-48.0.2564.116_p1
> x11-base/xorg-server-1.18.1 USE=glamor
> x11-wm/i3-4.11
>
> Hardware: DELL E7440 Haswell, with HDMI monitor directly connected, DP
> monitor connected through dock port.
>
> Strange thing compared to previous comments is that Chrome slows down to a
> crawl *only* when moved to the third, DP monitor. Everything works OK when
> chrome is sent to laptop eDP panel, or HDMI monitor.
>
> Launching with
>
> $ LIBGL_DRI3_DISABLE=1 google-chrome-stable
>
> successfully works around the problem, so seems to indicate this bug is the
> right place to be. Let me know if there's another, possibly more accurate
> bug available.
>
> What's the possible next step here?

Please send me your Xorg logs. I want to make sure you really are using the intel driver and not the modesetting driver.