Screen often flickers when using auto repeat on CR key or up-down cursor key to scroll the xterm fast. Was OK in 4.3.0 - first appears in 4.4-rc1 and still present in 4.4-rc3 and 4.4-rc4. I found a more reliable/repeatable test is (with auto-repeat enabled) to press any keyboard key (eg CR or hash) continuously and move mouse around within the same xterm (or vte). The screen area below the mouse flickers and is slightly darker than the top of the screen. Using "xset r off" to turn off auto-repeat and then typing hash rapidly while moving the mouse in the window also produced flicker. I get the flicker problem with xterm and vte -- but all is ok with rxvt and xfce4-terminal. I tried to see what "xwd" would capture of the screen - but while xwd is waiting for the mouse button to be pressed the screen is always stable - the flicker appearing again only after the mouse button is pressed. There are no errors logged during the flicker. I normally use icewm but get the same results with twm. ------------------------------------ Hardware: Asus P7H55-M SI with Intel Core i5 processor and Integrated Graphics [i915 driver]. Currently using a keyboard connected to a PS/2 keyboard port and using a USB connected mouse. Distro: Slackware-14.1, but with newer kernel. xterm -version gives :- X.Org 7.6.0(297) twm version 1.0.8 [Originally raised as kernel Bug 109021 but was redirected here.]
Update - have retested with 4.4-rc5 and get similar results to other 4.4-rc's. Also have checked the logs more carefully and noted a pair of error messages (always a pair) on xstartup with 4.4-rc1 through to rc5 (the ones with the flicker problem). The messages are absent on kernels up to and including 4.3.2. In /var/log/syslog using 4.4-rc5 at X startup got :- Dec 14 11:55:08 localhost kernel: [drm:ironlake_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun Dec 14 11:55:08 localhost kernel: [drm:ironlake_irq_handler [i915]] *ERROR* PCH transcoder A FIFO underrun
Have retested with 4.4.1 and 4.5-rc2 and get same flicker as with the 4.4-rc's.
(In reply to William from comment #2) > Have retested with 4.4.1 and 4.5-rc2 and get same flicker as with the > 4.4-rc's. Can you re-test with the latest drm-intel-nightly tree and see if this problem still happens? Specifically I'm hoping that this patch may have fixed your issue: commit b2435692dbb709d4c8ff3b2f2815c9b8423b72bb Author: Matt Roper <matthew.d.roper@intel.com> Date: Tue Feb 2 22:06:51 2016 -0800 drm/i915: Pretend cursor is always on for ILK-style WM calculations (v2) Also available here: http://patchwork.freedesktop.org/patch/72424/
Created attachment 121516 [details] Change to intel_pm.c I retested with 4.5-rc2 and your suggested patch 72424. The 4.5-rc2 is evidently slightly different to your baseline so I hand edited the drivers/gpu/drm/i915/intel_pm.c file to bring it into line with the patch. I will attach the old (4.5-rc2) and new versions of the changed function. It cured the flicker problem completely and the syslog file is now "clean". Thanks.
Relevant patch is now merged to -fixes and should show up in the next 4.5rc kernel.
The fix duly found its way into 4.5-rc5 onwards. The flicker problem was first found in 4.4-rc1 and as of 4.4.5 the flicker is still present. The same fix works with the 4.4.x series so would you do the same for 4.4.x - thanks.
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