https://bugzilla.kernel.org/show_bug.cgi?id=82781 Bug ID: 82781 Summary: Option to disable mclk reclocking with AMD R9 280X (TAHITI) to avoid screen flickering on VGA/CRT Product: Drivers Version: 2.5 Kernel Version: 3.16.1 Hardware: All OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: Video(DRI - non Intel) Assignee: drivers_video-dri@xxxxxxxxxxxxxxxxxxxx Reporter: joker@xxxxxxxxxxxx Regression: No I would like an option to forcefully disable mclk reclocking. Either as a module parameter or of course prefered at runtime as additional sysfs option in /sys/class/drm/card[n]/device probably with "power_<something>". The reason for this follows. I switched from a AMD 5570 to a R9 280X card. Both have working and stable DPM. With the new AMD R9 280X i noticed ocasiuonal screen flickering and narrowed it down to the mclk reclocking between "15000" level 0 and "160000" level 1-3. By connecting my TV over HDMI i noticed this would stop as multi head is known to disable mclk reclocking (I've checked si_dpm.c) I now hardcoded "disable_mclk_switching = true;" there and have a perfectly working flicker free screen. The sclk still changes fine and while probably not as power saving as full reclocking of course a lot better than totaly disabling DPM or forcing it to "low" and "high" based on the tasks i'm doing. I've also noticed this effect on Windows using proprietary drivers even tough a lot less than on Linux. Therefor i expect this to be a hardware related issue probably only visible on VGA analog out to CRT screens, so i fear it's not fixable in an automatic way. An option to manualy disable this feature in sysfs would help a lot. At runtime mclk reclocking could be reenabled while DPMS is on (aka. the screen is turned off). If this could be detected automaticaly it would be even better. -- You are receiving this mail because: You are watching the assignee of the bug. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
