On Fri, 01 Apr 2016, Rob Kramer <rob@xxxxxxxxxxxxxxxxxx> wrote: > My setup is an embedded GM45 based board with a screen connected via 24 > bit LVDS. When trying a to use a newer kernel (3.14.57) with KMS, the > screen stays blank. I'm only testing KMS so far, no X. Older, pre-KMS > versions of the kernel worked fine. > > I'm hoping that a resident Intel DRM guru has an idea of what might be > wrong here, or can tell me where to continue troubleshooting :) I'll put it bluntly, I don't think anyone's interested in troubleshooting v3.14 anymore. Please try v4.5. BR, Jani. > > I've uploaded a kernel log (drm.debug=0xe) here: > http://pastebin.com/nYNRGW5B > > The video kernel parameter for this log is: video=LVDS-1:1920x1080. I've > tried others, M and/or R suffixes, loading edid/1920x1080.bin etc, but > nothing works. I'm not sure if all this EDID timing stuff is even used > for LVDS.. > > One line in the log mentions a mode that is promising: > > [ 5.534021] [drm:intel_dump_crtc_timings], crtc timings: 148571 > 1920 2040 2080 2200 1080 1097 1108 1125, type: 0x0 flags: 0xa > > In the BIOS, the panel type is configured as "1920x1080@148.5M", so that > looks good. I have no idea where that modeline came from though. > > From what I can see, LVDS-1 and CRTC 3 are connected, but when it's > time to set the mode, it seems to have been modified into a bogus > adjusted mode: > > [ 5.570523] [drm:intel_dump_pipe_config], requested mode: > [ 5.570525] [drm:drm_mode_debug_printmodeline], Modeline > 0:"1920x1080" 0 172780 1920 2040 2248 2576 1080 1081 1084 1118 0x0 0x6 > [ 5.570526] [drm:intel_dump_pipe_config], adjusted mode: > [ 5.570529] [drm:drm_mode_debug_printmodeline], Modeline > 0:"640x480" 0 148571 640 656 752 800 480 490 492 525 0x8 0x0 > [ 5.570531] [drm:intel_dump_crtc_timings], crtc timings: 148571 > 640 656 752 800 480 490 492 525, type: 0x8 flags: 0x0 > > Also, the dot-clock mentioned in the HD mode is now 172780, for some > reason.. > > All sorts of kernel warnings follow, after this (what is LVDS-6?): > > [ 5.570569] [drm:intel_crtc_mode_set], [ENCODER:6:LVDS-6] set > [MODE:0:1920x1080] > > Please let me know if you'd like more logging or details. > > Cheers, > > Rob > > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
