Re: [PATCH 2/2] drm/i915: Don't treat FLR resets as errors

[Nirmoy Das <nirmoy.das@linux.intel.com>]

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Hi Andi,

On 5/17/2024 9:34 PM, Andi Shyti wrote:
> Hi Nirmoy,
>
> On Fri, May 17, 2024 at 04:00:02PM +0200, Nirmoy Das wrote:
>> On 5/17/2024 1:25 PM, Andi Shyti wrote:
>>> If we timeout while waiting for an FLR reset, there is nothing we
>>> can do and i915 doesn't have any control on it. In any case the
>>> system is still perfectly usable
>> If a FLR reset fails then we will have a dead GPU, I don't think the GPU is
>> usable without a cold reboot.
> fact is that the GPU keeps going and even though the timeout has
> expired, the system moves to the next phase.
The current test might look like it is has passed, but if you look into 
the subsequent tests you can see a dead GPU:

<7>[  369.168121] pci 0000:00:02.0: [drm:intel_uncore_fini_mmio [i915]] Triggering Driver-FLR
*<3>[ 372.170189] pci 0000:00:02.0: [drm] *ERROR* Driver-FLR-teardown 
wait completion failed! -110*
*<7>[ 372.437630] [IGT] i915_selftest: finished subtest requests, SUCCESS*
<7>[  372.438356] [IGT] i915_selftest: starting dynamic subtest migrate
<5>[  373.110580] Setting dangerous option live_selftests - tainting kernel
<3>[  373.183499] i915 0000:00:02.0: Unable to change power state from D0 to D0, device inaccessible
<3>[  373.246921] i915 0000:00:02.0: [drm] *ERROR* Unrecognized display IP version 1023.255; disabling display.
<7>[  373.247130] i915 0000:00:02.0: [drm:intel_step_init [i915]] Using future steppings
<7>[  373.247716] i915 0000:00:02.0: [drm:intel_step_init [i915]] Using future steppings
<7>[  373.248263] i915 0000:00:02.0: [drm:intel_step_init [i915]] Using future display steppings
<7>[  373.251843] i915 0000:00:02.0: [drm:intel_gt_common_init_early [i915]] WOPCM: 2048K
<7>[  373.252505] i915 0000:00:02.0: [drm:intel_uc_init_early [i915]] GT0: enable_guc=3 (guc:yes submission:yes huc:no slpc:yes)
<7>[  373.253140] i915 0000:00:02.0: [drm:intel_gt_probe_all [i915]] GT0: Setting up Primary GT
<7>[  373.253556] i915 0000:00:02.0: [drm:intel_gt_probe_all [i915]] GT1: Setting up Standalone Media GT
<7>[  373.253941] i915 0000:00:02.0: [drm:intel_gt_common_init_early [i915]] WOPCM: 2048K
<7>[  373.254365] i915 0000:00:02.0: [drm:intel_uc_init_early [i915]] GT1: enable_guc=3 (guc:yes submission:yes huc:yes slpc:yes)
*<3>[ 375.256235] i915 0000:00:02.0: [drm] *ERROR* Device is 
non-operational; MMIO access returns 0xFFFFFFFF!*
<3>[  375.259089] i915 0000:00:02.0: Device initialization failed (-5)
<3>[  375.260521] i915 0000:00:02.0: probe with driver i915 failed with error -5
<7>[  375.392209] [IGT] i915_selftest: finished subtest migrate, FAIL

https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_14724/bat-arls-3/dmesg0.txt

>
>> This is a serious issue and should be report as an error.  I think we need
>> to create a HW ticket to understand
>>
>> why is FLR reset fails.
> Maybe it takes longer and longer to reset. We've been sending
> several patches in the latest years to fix the timings.

HW spec says 3 sec but we can try increasing it bit higher to try it out.


Regards,

Nirmoy

>
> Andi

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