|Summary:||Black screen with KMS on powerpc iBook|
|Product:||xorg||Reporter:||Dan DeVoto <dand1972>|
|Component:||Driver/Radeon||Assignee:||xf86-video-ati maintainers <xorg-driver-ati>|
|Status:||NEW ---||QA Contact:||Xorg Project Team <xorg-team>|
|i915 platform:||i915 features:|
Description Dan DeVoto 2015-04-28 23:00:21 UTC
Created attachment 115416 [details] dmesg output In Debian Jessie, I get a black screen booting with KMS enabled. The backlight remains lit, but the screen displays as black. It happens on boot up about when these lines appear: [ 16.797096] [drm] Initialized drm 1.1.0 20060810 [ 18.117763] [drm] radeon kernel modesetting enabled. From then on I can log in blind, and I'm running pbbuttonsd so the brightness keys can dim or brighten the screen, but it always remains black. Switching to a console also gives me a black screen. Adding the kernel parameters video=offb:off radeon.modeset=1 radeon.agpmode=-1 changed nothing. This isn't a new problem, I've had it in previous Debian releases, but I hope someone might take a crack at this. Right now the only workaround is to disable KMS and work with a very slow desktop (and no mplayer or vlc fullscreen upscaling). This is on an G3 iBook (M8603LL/A - PowerBook4,3 - A1007) Thanks, Dan
Comment 1 Dan DeVoto 2015-04-28 23:01:29 UTC
Created attachment 115417 [details] output of cat /var/Xorg.0.log
Comment 2 Dan DeVoto 2015-04-28 23:02:18 UTC
Created attachment 115418 [details] output of lspci -vvv
Comment 3 Dan DeVoto 2015-07-27 06:03:57 UTC
Oddly, screen mirroring works perfectly. The external monitor shows my desktop as intended, but the iBook's screen remains bleak, I mean, black. I also generated a xorg.conf file to disable acceleration, but it didn't help.
Comment 4 Michel Dänzer 2015-07-30 02:49:58 UTC
This line in dmesg indicates a problem with the dot clock: [drm:drm_calc_timestamping_constants] *ERROR* crtc 14: Can't calculate constants, dotclock = 0!
Comment 5 Mathieu Malaterre 2016-04-14 07:12:40 UTC
The issue: [...] [drm:drm_calc_timestamping_constants] *ERROR* crtc 14: Can't calculate constants, dotclock = 0! [...] can also be seen here: https://bugs.freedesktop.org/show_bug.cgi?id=91428
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