This is a laptop with X700 Mobility (rv410). If I boot, then plug in the external VGA monitor, everything is fine and I can play with dual-screen. But if I boot with the external screen connected, the BIOS uses it for primary display and there's nothing on the LVDS. Then when X starts, I get the colourful slow "blooming" effect on the LVDS, which I once was explained happens when the output is enabled but the crtc is not on(?). Changing VT or restarting X does not help. Tested with latest git, on xserver 1.5.2 (Ubuntu 8.10 Beta). (Will attach logs, just need to find them)
Created attachment 19751 [details] log when booting with external VGA connected
Created attachment 19752 [details] verbose xrandr output (VGA connected)
It looks like the xserer is not properly taking into account the crtc limitations of the outputs when setting up the output topology: VGA-0 connected 1024x768+0+0 (0x55) normal (normal left inverted right x axis y axis) 304mm x 228mm Clones: DVI-0 CRTC: 0 CRTCs: 0 1 LVDS connected (normal left inverted right x axis y axis) Clones: CRTCs: 0 crtc 0 gets assigned to VGA-0, and since LVDS is restricted to crtc 0 does not allow cloning I suspect it ends up in some kind of undefined state (on but being driven by the crtc timing for VGA-0 probably rather than native panel timing). The xrandr core code used to work correctly in this case. Any chance you could bisect the xserver to find out what change broke this?
Created attachment 19768 [details] log from old server 7.2 I don't know if this ever worked. I usually don't use dual screen, just borrowed a monitor for another reason and wanted to check out and look for trouble. Having a pile of old live CDs, I tried Ubuntu 7.04 which has server 7.2 and I think the first version of -ati that would work on this laptop due to a patch from bug 5473. Here clone is disabled because it "Failed to detect secondary monitor".
Created attachment 19769 [details] log from old server 1.4 This is the log from Ubuntu 8.04 with xserver 1.4 and an up-to-date -ati, same results as with xserver 1.5.2.
Created attachment 19770 [details] xrandr verbose output, xserver 1.4 I tried moving VGA-0 to crtc 1, and then enable LVDS, but that doesn't help.
I have a very similar problem, it helped to upgrade to xf86-video-ati 6.12.1 and enable R4xxATOM (see bug 13533 comment 24). It caused bug 20814 for me, but a patch for that was checked into git recently.
Created attachment 30537 [details] xrandr output, after booting with external monitor I tried again now with 1.6.4 and 6.12.99+git20090929. The LVDS is still blooming, but xrandr indicates LVDS is correctly on crtc 0, so this can not be the problem. After suspend/resume the screen works again. OTOH, xrandr --off on both screens, then both or one of them back with --auto, does not help.
Mass closure: This bug has been untouched for more than six years, and is not obviously still valid. Please file a new report if you continue to experience issues with a current server.
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