Launchpad has imported 13 comments from the remote bug at https://bugs.freedesktop.org/show_bug.cgi?id=92685.
If you reply to an imported comment from within Launchpad, your comment will be sent to the remote bug automatically. Read more about Launchpad's inter-bugtracker facilities at https://help.launchpad.net/InterBugTracking. ------------------------------------------------------------------------ On 2015-10-27T01:43:10+00:00 Eric Biggers wrote: Created attachment 119210 dmesg.gz Running Linux 4.3-rc7 on a laptop with Intel Skylake integrated graphics, I encountered warnings in the kernel log and a several second hang during boot. Furthermore, an external monitor attached to the HDMI input did not work. The problems occur every boot. The full dmesg output with drm.debug=14 is attached; some highlights are shown below: [ 1.401196] [drm:intel_dp_aux_ch] *ERROR* dp aux hw did not signal timeout (has irq: 1)! [ 1.414508] [drm:intel_dp_aux_ch] *ERROR* dp aux hw did not signal timeout (has irq: 1)! [ 1.427851] [drm:intel_dp_aux_ch] *ERROR* dp aux hw did not signal timeout (has irq: 1)! [ 1.427853] [drm:intel_dp_aux_ch] *ERROR* dp_aux_ch not done status 0xad40001f [ 1.447865] ------------[ cut here ]------------ [ 1.447867] WARNING: CPU: 1 PID: 6 at drivers/gpu/drm/i915/intel_dp.c:854 intel_dp_aux_ch+0x10f/0x6a0() [ 1.447867] dp_aux_ch not started status 0xad40001f ... [ 8.043643] [drm:drm_edid_block_valid] *ERROR* EDID checksum is invalid, remainder is 130 ... [ 32.571277] [drm:drm_edid_block_valid] *ERROR* EDID checksum is invalid, remainder is 130 ... [ 32.608835] i915 0000:00:02.0: HDMI-A-1: EDID block 0 invalid. Reply at: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1572901/comments/0 ------------------------------------------------------------------------ On 2015-10-28T14:30:48+00:00 Timo Aaltonen wrote: seeing same on SKL21-SDS, with the added fun that eDP stays blank until drm-intel-next-2015-09-28-merged. Reply at: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1572901/comments/1 ------------------------------------------------------------------------ On 2015-10-28T14:35:55+00:00 Timo Aaltonen wrote: ..until the first DPMS cycle, returning from it makes things work Reply at: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1572901/comments/2 ------------------------------------------------------------------------ On 2015-11-13T14:24:56+00:00 Ander Conselvan de Oliveira wrote: Created attachment 119641 Fix SKL DP AUX CH clock divider Could you give this patch a try? Reply at: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1572901/comments/3 ------------------------------------------------------------------------ On 2015-11-13T14:35:08+00:00 Ander Conselvan de Oliveira wrote: Created attachment 119642 Fix SKL DP AUX CH clock divider There was a typo on the previous patch. Reply at: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1572901/comments/4 ------------------------------------------------------------------------ On 2015-11-14T01:21:35+00:00 Eric Biggers wrote: I tested Linux 4.3 with your patch applied, but it did not solve the problem. Reply at: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1572901/comments/5 ------------------------------------------------------------------------ On 2015-11-23T03:20:49+00:00 Eric Biggers wrote: Update: with Linux 4.4-rc2, the "dp_aux_ch not started" warning is gone, and there is no longer a several second hang on boot or when changing the screen resolution. However, the HDMI output continues to be broken, and the log messages about the EDID checksum being invalid still appear. Reply at: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1572901/comments/6 ------------------------------------------------------------------------ On 2015-11-25T05:51:20+00:00 Eric Biggers wrote: I updated the bug title to reflect the fact that the HDMI output not working (because of the invalid EDID checksum) is now the only problem for me. So there must have been two separate problems originally, one of which was solved by the 4.4 merges. I tried hacking the i915 driver code in a few different ways but none of them solved the problem: - always setting force_bit=1 on the 'struct intel_gmbus' - changing the drm_i915_private hotplug_work to a delayed_work and scheduling it with delay 400 ms - increasing the number of retries in drm_do_get_edid() from 4 to 32 - increasing the number of retries of the "live status" check in intel_hdmi_detect() from 3 to 30 Also, I verified that the same monitor and VGA->HDMI adapter works on a Raspberry Pi. So that leaves the Skylake hardware and/or the i915 driver as the source of the problem. Reply at: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1572901/comments/7 ------------------------------------------------------------------------ On 2015-11-25T08:11:39+00:00 Jani-nikula wrote: Please add drm.debug=14 module parameter, and attach dmesg all the way from boot to the problem, running v4.4-rc2 or later. Please attach plain text dmesg only, not compressed. Reply at: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1572901/comments/8 ------------------------------------------------------------------------ On 2015-11-26T02:47:51+00:00 Eric Biggers wrote: Created attachment 120126 dmesg Reply at: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1572901/comments/9 ------------------------------------------------------------------------ On 2015-11-26T02:50:56+00:00 Eric Biggers wrote: Attached the log as requested. Reply at: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1572901/comments/10 ------------------------------------------------------------------------ On 2016-01-24T17:16:45+00:00 Eric Biggers wrote: Update: Using a different cable, which connects the DVI input of the monitor to the HDMI output of the Skylake GPU, everything works as expected. The non-working setup used a different adapter that connected the VGA input of the monitor to the HDMI output of the Skylake GPU. So, the issue manifests itself with particular adapters and not with the HDMI output itself. It's also possible that everything works as intended on the Skylake side and the particular (brand new) adapter I used was "bad". However, I don't currently have any other HDMI->VGA adapters to test. I will leave this bug open for now as several people are watching it, and it's possible they have encountered similar problems. Reply at: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1572901/comments/11 ------------------------------------------------------------------------ On 2016-01-25T09:19:37+00:00 Jani-nikula wrote: HDMI->DVI is just wires. HDMI->VGA is an active protocol converter. The more complex stuff always has more ways to go wrong, both in the adapter and in the driver. Reply at: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1572901/comments/12 ** Changed in: linux Status: Unknown => Confirmed ** Changed in: linux Importance: Unknown => Medium -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1572901 Title: i915: No HDMI output with 4.4 To manage notifications about this bug go to: https://bugs.launchpad.net/linux/+bug/1572901/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
