[Intel-gfx] [PATCH v2 1/2] drm/i915/guc: Use correct error code for GuC initialization failure

[Michal Wajdeczko]

On Wed, 21 Feb 2018 09:27:51 +0100, Chris Wilson  
<chris at chris-wilson.co.uk> wrote:

> Quoting Michal Wajdeczko (2018-02-20 22:57:10)
>> Since commit 6ca9a2beb54a ("drm/i915: Unwind i915_gem_init() failure")
>> we believed that we correctly handle all errors encountered during
>> GuC initialization, including special one that indicates request to
>> run driver with disabled GPU submission (-EIO).
>>
>> Unfortunately since commit 121981fafe69 ("drm/i915/guc: Combine
>> enable_guc_loading|submission modparams") we stopped using that
>> error code to avoid unwanted fallback to execlist submission mode.
>>
>> In result any GuC initialization failure was treated as non-recoverable
>> error leading to driver load abort, so we could not even read related
>> GuC error log to investigate cause of the problem.
>>
>> Fix that by always returning -EIO on uC hardware related failure.
>>
>> v2: don't allow -EIO from uc_init
>>     don't call uc_fini[_misc] on -EIO
>>     mark guc fw as failed on hw init failure
>>     prepare uc_fini_hw to run after earlier -EIO
>>
>> Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
>> Cc: Chris Wilson <chris at chris-wilson.co.uk>
>> Cc: Michal Winiarski <michal.winiarski at intel.com>
>> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
>> Cc: Sagar Arun Kamble <sagar.a.kamble at intel.com>
>
> Whilst thinking about this, do you want to disable (or rather prevent
> setup of) guc submission if the driver is already wedged?

We setup GuC submission in intel_uc_init_hw() and just before we call
it from i915_gem_init_hw() we already have a check for wedged driver.
So maybe we don't want to add redundant guard ?

/Michal