iMac connected to MacBook in Target Display Mode shows black screen

[paniq]

*** Fixed in linux 3 rc1 ***

Since this is similar to bug #597070, but covers remote displays instead of direct installations of Ubuntu on iMacs, I thought I'd file this as a separate bug report.

The setup is a MacBook 8,1 running Ubuntu 11.04 connected to a 27" iMac via a crosslink Mini DisplayPort cable. The iMac mirrors output when the GRUB screen is reached, but then remains black for the rest of the session.

When starting Ubuntu in Unity mode with effects enabled, the MacBook fails to update the screen once the iMac is connected. It either goes black or freezes, with the cursor still intact. The iMac remains dark.

When starting Ubuntu in classic mode without effects, the MacBook screen works as usual without freezing. When the display port is plugged in, the display goes blank for a second, but then returns properly. Yet, the iMac remains dark.

Still, the iMac is properly recognized. Via the "Monitors" configuration dialog, I can set its proper resolution and arrange it, yet it doesn't react.

The video card is an Intel one - I can't get the exact model right now, but the responsible kernel module is called "i915".

[Fabio Marconi (fabiomarconi)]

Hello
can you please reproduce the bug, and attach here, using the button below 'Add attachment or patch', the files:
/var/log/Xorg.0.log.old
/var/log/Xorg.0.log
/var/log/kern.log
/var/log/dmesg
Thanks
Fabio

[paniq (paniq)]

Attached is the requested set of log files. The computer has already been running for a while - I plugged the iMac in twice .

The monitor tools recognizes the external monitor and shows it in the layout pane, but then reverts back to a single screen layout and the iMac turns off remote mode again.

[Fabio Marconi (fabiomarconi)]

Jun 1 09:34:20 over9000 kernel: [ 1165.797324] [drm:i915_hangcheck_ring_idle] *ERROR* Hangcheck timer elapsed... blt ring idle [waiting on 736878, at 736878], missed IRQ?
Jun 1 09:34:58 over9000 kernel: [ 1204.385049] [drm:i915_hangcheck_ring_idle] *ERROR* Hangcheck timer elapsed... blt ring idle [waiting on 753330, at 753330], missed IRQ?
Jun 1 09:44:09 over9000 kernel: [ 1755.019902] [drm:i915_hangcheck_ring_idle] *ERROR* Hangcheck timer elapsed... blt ring idle [waiting on 1164358, at 1164358], missed IRQ?
Jun 1 09:47:32 over9000 kernel: [ 1958.145315] [drm:i915_hangcheck_ring_idle] *ERROR* Hangcheck timer elapsed... blt ring idle [waiting on 1285369, at 1285369], missed IRQ?
Jun 1 09:51:25 over9000 kernel: [ 2190.381424] [drm:i915_hangcheck_ring_idle] *ERROR* Hangcheck timer elapsed... blt ring idle [waiting on 1409890, at 1409890], missed IRQ?

[Fabio Marconi (fabiomarconi)]

Jun 1 14:07:00 over9000 kernel: [17520.804327] show_signal_msg: 27 callbacks suppressed
Jun 1 14:07:00 over9000 kernel: [17520.804332] polkit-gnome-au[1631]: segfault at 2007534 ip 00007fc14f6d09d8 sp 00007fffe6387bf0 error 4 in libglib-2.0.so.0.2800.6[7fc14f6a9000+ed000]
Jun 1 14:07:12 over9000 kernel: [17533.027882] eclipse[10408] trap divide error ip:7f97851f0788 sp:7fffc5495e40 error:0 in libgtk-x11-2.0.so.0.2400.4[7f97850c5000+436000]
Jun 1 14:11:25 over9000 kernel: [17786.054458] HDMI hot plug event: Pin=5 Presence_Detect=1 ELD_Valid=0
Jun 1 14:11:26 over9000 kernel: [17786.475289] [drm:intel_dp_complete_link_train] *ERROR* failed to train DP, aborting
Jun 1 14:13:07 over9000 kernel: [17888.078536] [drm:ironlake_crtc_disable] *ERROR* failed to disable transcoder
Jun 1 14:13:08 over9000 kernel: [17888.562827] [drm:intel_dp_complete_link_train] *ERROR* failed to train DP, aborting

[Fabio Marconi (fabiomarconi)]

Hello
Can you please install the latest mainline kernel, clicking on these links:

1 - http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.0-rc1-oneiric/linux-headers-3.0.0-0300rc1_3.0.0-0300rc1.201105310830_all.deb

2 - http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.0-rc1-oneiric/linux-headers-3.0.0-0300rc1-generic_3.0.0-0300rc1.201105310830_amd64.deb

3 - http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.0-rc1-oneiric/linux-image-3.0.0-0300rc1-generic_3.0.0-0300rc1.201105310830_amd64.deb

and refere if fix the issue.
Thanks
fabio

[paniq (paniq)]

Will try on monday, as the setup is at work and the next two days are holidays. Does this kernel work with 11.04? Could I revert back to the old one afterwards?

[Fabio Marconi (fabiomarconi)]

Hello
Sure it works, you can revert back to the old kernel:
booting the pc press coninuosly the left shift to recall grub menu and select to start from the older kernel, when booted using Synaptic type linux in the search box and so you can easily remove the instaled linux packages.
Fabio

[paniq (paniq)]

Success!

Installed and booted the new kernel without a problem, plugged in cable at log-in, iMac comes on, screen is properly shared.

Thanks a lot!

[Fabio Marconi (fabiomarconi)]

fixed in linux 3

[Fabio Marconi (fabiomarconi)]

Hello paniq
Thanks for the reply
I close this report as Fix released
Thanks
Fabio