Bug 91876

Summary: [SKL EDP] DP Aux A is not working without first disabling DC6
Product: DRI Reporter: Patrik Jakobsson <patrik.r.jakobsson>
Component: DRM/IntelAssignee: Intel GFX Bugs mailing list <intel-gfx-bugs>
Status: CLOSED FIXED QA Contact: Intel GFX Bugs mailing list <intel-gfx-bugs>
Severity: normal    
Priority: medium CC: intel-gfx-bugs, tjaalton
Version: DRI git   
Hardware: Other   
OS: All   
Whiteboard:
i915 platform: SKL i915 features: display/eDP
Attachments:
Description Flags
dmesg none

Description Patrik Jakobsson 2015-09-04 13:07:03 UTC
Created attachment 118078 [details]
dmesg

DP Aux A is not working without first disabling DC6. Not really a regression but since commit a7f749f9c7e8222405740f6081bd183137d1d6f2 the DMC is working and we can enter DC states which made this bug visible. The result is that modesetting takes a few seconds but still succeeds.

We get a few of these:
[drm:intel_dp_aux_ch [i915]] *ERROR* dp aux hw did not signal timeout (has irq: 1)!

Before finally giving up with:
[drm:intel_dp_aux_ch [i915]] *ERROR* dp_aux_ch not done status 0xad40001f

I'm currently writing code to allow for power domain get/put to disable/enable dc states for platform restrictions.
Comment 1 Patrik Jakobsson 2015-09-11 11:59:05 UTC
Submitted an RFC patch to address this issue
http://lists.freedesktop.org/archives/intel-gfx/2015-September/075691.html
Comment 2 Timo Aaltonen 2015-09-19 06:20:01 UTC
*** Bug 92037 has been marked as a duplicate of this bug. ***
Comment 3 Patrik Jakobsson 2015-11-04 09:48:06 UTC
DC6 is currently disabled at runtime so this issue no longer exists. DC6 will be re-enabled but at that point we'll have a power well for "DC off" which Aux A will grab.

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