https://bugzilla.kernel.org/show_bug.cgi?id=58021
Summary: [BISECTED] nouveau, nv50: External VGA not detected anymore Product: Drivers Version: 2.5 Kernel Version: 3.7.0-rc4+ - 3.9 Platform: All OS/Version: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: Video(DRI - non Intel) AssignedTo: drivers_video-dri@kernel-bugs.osdl.org ReportedBy: wippbox@gmx.net Regression: No
Created an attachment (id=101211) --> (https://bugzilla.kernel.org/attachment.cgi?id=101211) dmesg for last good commit
I have a lenove thinkpad T61p with a NVIDIA Corporation G84GLM [Quadro FX 570M]. When connecting my external VGA monitor my monitor is no more detected properly:
cat /sys/class/drm/card0-VGA-1/status
gives now "disconnected"
Last good commit is ef22c8bb7b3fac45919b7fde412d36d1a8367d51 drm/nv50/disp: call into core to handle dac/sor power state changes
First bad commit is 7ebb38b556485449bfaa506a196439f6a6fd6ebd drm/nv50/disp: call into core for dac load detection
The responsible function is nv50_dac_detect in drivers/gpu/drm/nouveau/nv50_dac.c (moved to drivers/gpu/drm/nouveau/nv50_display.c in more recent kernels).
Also tried a 3.9.1 kernel. The problem still remains.
However, replacing nv50_dac_detect with the corresponding version from the last good commit fixed the problem (tried a 3.8.10 kernel).