[Intel-gfx] Skylake 6700k Intel HD Graphics 530 Display Port Panic

[Zhang, Xiong Y]

I see the similar error message on one SKL machine, but DP system works well and system doesn't panic.
I resolved it by one of the following three method, maybe you could try it.
1) boot with i915.disable_power_well=0
2)delete /lib/firmware/i915/skl_dmc_ver1.bin
3) apply the patch set in http://lists.freedesktop.org/archives/intel-gfx/2015-August/072870.html

thanks
> -----Original Message-----
> From: Intel-gfx [mailto:intel-gfx-bounces at lists.freedesktop.org] On Behalf Of
> Matthew Minter
> Sent: Sunday, September 6, 2015 12:34 PM
> To: intel-gfx at lists.freedesktop.org
> Subject: [Intel-gfx] Skylake 6700k Intel HD Graphics 530 Display Port Panic
> 
> Hello,
> 
> I am currently trying to set up a newly built system with a Skylake
> 6700k CPU but am having an extremely
> reproducible kernel panic every time I connect a monitor to the display
> port connector of the Intel
> integrated graphics chip.
> 
> This issue occurs either immediately upon connecting a display port
> monitor to the machine while it is up
> or late in the boot process if the display port is connected at boot
> time.
> 
> The monitor which I am using is a Dell U3415W ultra wide and the
> motherboard is a MSI Z170A Gaming M7.
> 
> I am not entirely surprised by the link train errors as there appear to
> be various posts about users having
> problems with this monitor and display port training, what surprises me
> most is the fact it is causing a kernel panic.
> 
> Upon the panic happening the kernel prints the following dump (to the
> second non DP monitor), (note this is hand copied as I
> have no way to dump the messages anywhere but the display so pardon any
> small typos).
> 
> [   22.318630]  [drm:intel_dp_start_link_traln [i915]] *ERROR* too many
> full retries, give up
> [   22.365449]  [drm:intel_dp_start_link_traln [i915]] *ERROR* too many
> full retries, give up
> [   22.420272]  [drm:intel_dp_start_link_traln [i915]] *ERROR* too many
> full retries, give up
> [   22.475105]  [drm:intel_dp_start_link_traln [i915]] *ERROR* too many
> full retries, give up
> [   22.529931]  [drm:intel_dp_start_link_traln [i915]] *ERROR* too many
> full retries, give up
> [   22.584759]  [drm:intel_dp_start_link_traln [i915]] *ERROR* too many
> full retries, give up
> [   22.639588]  [drm:intel_dp_start_link_traln [i915]] *ERROR* too many
> full retries, give up
> [   22.649935]  [drm:intel_dp_start_link_traln [i915]] *ERROR* too many
> full retries, give up
> [   22.650532]  [drm:intel_dp_start_link_traln [i915]] *ERROR* too many
> full retries, give up
> [   24.329955]  Kernel panic - not syncing: Timeout: Not all CPUs
> entered broadcast exception handler
> [   25.345911]  Shutting down cpus with NMI
> [   25.356092]  Kernel offset: disabled
> [   25.356101]  Rebooting in 30 seconds.
> 
> If running kernel 4.2 occasionally these errors are followed by what
> seems to be a an mce machine check exception mentioning
>   a corrupt processor context which is very hard to note down as it is
> only on the screen very briefly. However if running the
> latest kernel from https://github.com/torvalds/linux only the above
> error occurs, not the mce exception. I am pretty confident
> the mce exception is spurious due to this and the fact the system
> otherwise tests out fine.
> 
> I apologise if this report is a little sparse on details, it is very
> hard to post mortem debug the system due to the panic and
> the fact I have no available serial terminal or hardware debugger.
> 
> Otherwise the system flawlessly passes memtest86+ and is completely
> stable even under heavy load.
> This issue seems to occur on every kernel I have tested so far including
> a stock ubuntu 15.4, a vanilla 4.0.5 kernel,
> a vanilla 4.2.0 kernel and the head of https://github.com/torvalds/linux
> as of a few hours ago.
> 
> The kernel config used for the kernel taken from git is available here:
> http://paste2.org/MH9vV4Le
> The 4.2 and 4.0.5 configs were extremely similar and only differ in the
> new entries made by oldconfig.
> 
> If there is anything I can do to produce more info I am more than happy
> to do so.
> Or if this is not the right mailing list for this issue please let me
> know where would be better.
> 
> Many thanks,
> Matthew
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