On Fri, Apr 27, 2012 at 8:39 PM, Nick Bowler nbowler@elliptictech.com wrote:
Hi Ben,
On 2012-04-27 15:20 +1000, Ben Skeggs wrote:
Does this patch help you at all?
http://cgit.freedesktop.org/nouveau/linux-2.6/commit/?id=a3a285f17867f0018de...
Yes. I cherry-picked this patch on top of Linus' master (3.4-rc4+) and this appears to solve the "black screen on VGA" problem described in the original report. Thanks!
Unfortunately, that's not the end of my VGA-related regressions. :(
While tracking down the black screen issue, I've been having the monitor directly connected to the video card the whole time, but now when I'm connected through my KVM switch (an IOGear GCS1804), it appears that something's going wrong with reading the EDID, because the available modes are all screwed up (both console and X decide they want to drive the display at 1024x768). Here's the output of xrandr on 3.2.15:
% xrandr Screen 1: minimum 320 x 200, current 1600 x 1200, maximum 4096 x 4096 VGA-1 connected 1600x1200+0+0 (normal left inverted right x axis y axis) 352mm x 264mm 1600x1200 75.0*+ 70.0 65.0 60.0 1280x1024 85.0 + 75.0 60.0 1920x1440 60.0 1856x1392 60.0 1792x1344 60.0 1920x1200 74.9 59.9 1680x1050 84.9 74.9 60.0 1400x1050 85.0 74.9 60.0 1440x900 84.8 75.0 59.9 1280x960 85.0 60.0 1360x768 60.0 1280x800 84.9 74.9 59.8 1152x864 75.0 1280x768 84.8 74.9 59.9 1024x768 85.0 75.1 75.0 70.1 60.0 43.5 43.5 832x624 74.6 800x600 85.1 72.2 75.0 60.3 56.2 848x480 60.0 640x480 85.0 75.0 72.8 72.8 66.7 60.0 59.9 720x400 85.0 87.8 70.1 640x400 85.1 640x350 85.1 320x200 165.1
And on 3.4-rc4+ (with your patch cherry-picked):
% xrandr Screen 1: minimum 320 x 200, current 1024 x 768, maximum 4096 x 4096 VGA-1 connected 1024x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm 1024x768 60.0* 800x600 60.3 56.2 848x480 60.0 640x480 59.9 320x200 165.1
Running xrandr on 3.4-rc4+ also causes the screen to go black for a second when it does not on 3.2.15. It also causes several messages of the form
[drm] nouveau 0000:01:00.0: Load detected on output B
to be logged. Also, looking at /sys/class/drm/card0-VGA-1/edid I see that it is empty on 3.4-rc4+ and it is correct on 3.2.15. Things seem to work OK when the KVM is not involved.
Were you ever able to fetch a EDID with the KVM involved? KVMs are notorious for not connecting the ddc pins.
Alex