https://bugs.freedesktop.org/show_bug.cgi?id=48772
Bug #: 48772 Summary: Signal unstable over Display Port on 2560x1440 monitor Classification: Unclassified Product: DRI Version: XOrg CVS Platform: Other OS/Version: All Status: NEW Severity: normal Priority: medium Component: DRM/Radeon AssignedTo: dri-devel@lists.freedesktop.org ReportedBy: tvrtko.ursulin@onelan.co.uk
AMD G-T56N (Radeon HD 6310) hardware with kernel 3.4-rc3 with a Xorg DDX from 28.03.2012. plus a tiling patch from bug 47765.
Dell U2711 monitor native resolution is 2560x1440 on which Display Port connection is unstable.
I get periodic very brief flashes of vertical noise areas, full screen width, at various vertical positions, but possible always at least roughly the same height. Then the screen goes black for a second, comes back for a while, flashing, or straight back to black and so on. Timings do not look regular, although I haven't actually timed and analysed them.
Bringing the resolution down to 1920x1200 and it works fine.