Created attachment 50752 [details] kernel log with drm.debug=0x06 System: Intel 2600K Intel DH67GD motherboard Ubuntu Oneiric with 3.0.0-9-generic-pae kernel Apple 27 iMac connected as an external monitor via displayport. On boot the iMac switches to the displayport input and shows the motherboard boot screen and grub but the screen goes dark when it gets into the graphical part of the boot and stays that way. I have also tried with the Fedora 16 alpha live disk and the same thing seems to happen.
Created attachment 50753 [details] Xorg log from same boot
There was some brief discussion on this a few months ago: http://lists.freedesktop.org/archives/intel-gfx/2011-April/010479.html There are some differences since then (I seem to get modeline in the new logs) but no real difference.
Created attachment 50832 [details] 3.1.0-rc4 kern.log with drm.debug=0x06
Created attachment 52814 [details] Log from newer kernel Partial log (grepped for drm) from newer kernel. I wanted to build from drm-intel-next but did not work out how pull and build it myself so Kernel is linux-image-3.1.0-997-generic_3.1.0-997.201110240423_i386.deb from http://kernel.ubuntu.com/~kernel-ppa/mainline/drm-intel-next/
This would be worth retesting with the latest kernel as it contains a number of bandwidth calculation fixes for DP.
To be more precise, you need 3.4-rc3 to get all the latest fixes.
Created attachment 61003 [details] kernel log from a 3.4.0 drm-intel-experimental kernel This is a log from a boot with the pae kernel from: http://kernel.ubuntu.com/~kernel-ppa/mainline/drm-intel-experimental/2012-05-03-precise/ which was the most recent one I could find. Same on screen behaviour as before, screen goes dark once past the text part of the boot process.
Presumably fixed with the prefer lanes-over-bw patch: commit 2514bc510d0c3aadcc5204056bb440fa36845147 Author: Jesse Barnes <jbarnes@virtuousgeek.org> Date: Thu Jun 21 15:13:50 2012 -0700 drm/i915: prefer wide & slow to fast & narrow in DP configs This patch is merged into 3.6-rc1. If this is still an issue on kernels containing this patch, please reopen. If you reopen, please also attach a new dmesg (again with drm.debug=0xe), but please ensure that it contains everything from boot-up (the current one is cut off at the beginning).
Created attachment 66195 [details] Kernel log from 3.6rc3 Tested using i386 builds from: http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.6-rc3-quantal/ Still get a dark screen after bios.
The dmesg is cut off at the beginning, you need to increase the dmesg buffer by adding log_buf_len=2M to the kernel cmdline. Please ensure that the entire dmesg is captured when attaching it, otherwise please increase the dmesg buffer some more.
Created attachment 66383 [details] Better log from 3.6.0 rc3 Sorry the previous log wasn't sufficient
Is this still broken in current kernels and/or drm-intel-next-queued? Too many changes to count since 3.6.0-rc3, most of them affecting mode setting.
Assuming fixed with the DP rework in 3.7. Please do reopen if you it is not fixed and can provide the updated log files.
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