Created attachment 18068 [details] X log I'm not sure when, but I recently found that X is generating a lot of bad modes. This is xrandr output: Screen 0: minimum 320 x 200, current 1280 x 1024, maximum 1400 x 1400 VGA-0 connected 1280x1024+0+0 (normal left inverted right x axis y axis) 338mm x 270mm 1280x1024 60.0*+ 75.0 60.0* 1400x1050 60.0 1280x960 60.0 1152x864 75.0 1024x768 85.0 75.0 70.1 60.0 832x624 74.6 800x600 130.0 120.0 85.1 85.1 72.2 75.0 60.3 56.2 700x525 149.5 120.0 640x512 150.0 120.0 640x480 120.0 85.0 75.0 72.8 75.0 66.7 59.9 720x400 85.0 70.1 640x400 85.1 576x432 150.0 640x350 85.1 512x384 170.0 150.1 140.1 120.0 416x312 149.3 400x300 170.5 144.4 150.2 120.6 112.7 320x240 170.4 145.6 150.0 120.1 360x200 170.1 320x200 170.5 320x175 170.5 This is a flat panel, and I'm quite sure it cannot accept modes above 85Hz, maybe even lower. Furthermore, according to the log, there are lots of doublescan modes. When anything switches to 800x600 mode, X picks a doublescan mode, which won't work. If I manually do 'xrandr -s 800x600 -r 60' the mode is good. Additionally, the included X log contains a line like the following for every mode switch: (II) NOUVEAU(0): Modeline "(null)"x0.0 108.00 1280 1328 1440 1688 1024 1025 1028 1066 +hsync +vsync (64.0 kHz) which is clearly a NULL dereference, but the gnu vsnprintf is so cool it doesn't crash. I'm running xorg-server and nouveau from git as of 1.8.2008.
After discussion with malc0 and stillunknown, I'm reassigning this to xorg-server. EDID reported monitor freq ranges: V min: 50 V max: 85 Hz, H min: 30 H max: 82 kHz, PixClock max 140 MHz. There are several doublescan modes that actually fit into the freq ranges, especially 800x600@65D. Xrandr reports doublescan modes by showing the refresh rate as double, which can be seen in the xrandr output in the previous comment. As higher refresh rates are automatically favoured, this means doublescan modes get priority. E.g. 800x600@65D is in randr1.2 speak 800x600@130, which is then preferred over all normal 800x600 modes. As the monitor cannot deal with doublescan modes, I don't get a picture by default.
Created attachment 18319 [details] X log with ModeDebug Perhaps a better log with ModeDebug enabled. Contains X startup, xrandr -s 800x600 and xrandr -s 0.
Created attachment 18321 [details] xorg.conf I tried adding TargetRefresh, but the only effect is the message: (WW) NOUVEAU(0): Option "TargetRefresh" is not used
Changing the bug summary a little more descriptive.
Something has changed, xrandr does not list doublescan modes anymore: $ xrandr Screen 0: minimum 320 x 200, current 800 x 600, maximum 1280 x 1280 VGA-0 connected 800x600+0+0 (normal left inverted right x axis y axis) 338mm x 270mm 1280x1024 60.0 + 75.0 60.0 1152x864 75.0 1024x768 85.0 75.0 70.1 60.0 832x624 74.6 800x600 85.1* 72.2 75.0 60.3 56.2 640x480 85.0 75.0 72.8 66.7 59.9 720x400 70.1 The xorg.log used to list doublescan modes, now they are gone. My guess is that either updating xorg-server or Nouveau from git did this. The xrandr application is still 1.2.2. Therefore I'm marking this as fixed, although I cannot pinpoint the fix.
*** Bug 19214 has been marked as a duplicate of this bug. ***
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