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.
Submitted an RFC patch to address this issue http://lists.freedesktop.org/archives/intel-gfx/2015-September/075691.html
*** Bug 92037 has been marked as a duplicate of this bug. ***
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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