[Bug 92932] [SKL] intel_dp_start_link_train ERROR 5.4Gbps rate without HBR2/TPS3 support

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=92932

--- Comment #6 from Timur Alperovich <timur.alperovich at gmail.com> ---
Jani, I attempted to plug in a 4k monitor over the display port. The monitor
produced a black screen. At lower resolution (2560x1440), the image is
displayed, but at 3840x2160 I get a black screen with the following warnings:
[ 1814.843637] [drm:gen8_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun
[ 1815.628547] [drm:intel_dp_start_link_train [i915]] *ERROR* 5.4 Gbps link
rate without HBR2/TPS3 support

I'm also seeing this warning when attaching/removing a display:
[ 1806.466752] WARNING: CPU: 0 PID: 1434 at
drivers/gpu/drm/i915/intel_pm.c:3537 skl_update_other_pipe_wm+0x138/0x140
[i915]()
[ 1806.466754] WARN_ON(!wm_changed)

It seems benign however. If I switch to using HDMI and try the same resolution
as above at 30Hz, the image is also displayed correctly.

This is with the drm-intel-nightly build as of November 30th. Let me know if I
can do any other tests, open a different bug, or attach any logs that would be
helpful.

-- 
You are receiving this mail because:
You are the QA Contact for the bug.
You are on the CC list for the bug.
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/intel-gfx-bugs/attachments/20151201/4275d11c/attachment.html>