[Intel-gfx] [PATCH 6/6] drm/i915/guc: Grab RPM wakelock while disabling GuC interrupts

[Michal Wajdeczko]

On Thu, 14 Sep 2017 18:04:27 +0200, Kamble, Sagar A  
<sagar.a.kamble at intel.com> wrote:

>
>
> On 9/14/2017 6:07 PM, Michal Wajdeczko wrote:
>> On Thu, 14 Sep 2017 11:55:08 +0200, Sagar Arun Kamble  
>> <sagar.a.kamble at intel.com> wrote:
>>
>>> From: "Kamble, Sagar A" <sagar.a.kamble at intel.com>
>>>
>>> Disabling GuC interrupts involves access to GuC IRQ control registers
>>> hence ensure device is RPM awake.
>>>
>>> Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
>>> Signed-off-by: Sagar Arun Kamble <sagar.a.kamble at intel.com>
>>> ---
>>>  drivers/gpu/drm/i915/intel_guc_log.c | 2 ++
>>>  1 file changed, 2 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/i915/intel_guc_log.c  
>>> b/drivers/gpu/drm/i915/intel_guc_log.c
>>> index ba36162..d7557b5 100644
>>> --- a/drivers/gpu/drm/i915/intel_guc_log.c
>>> +++ b/drivers/gpu/drm/i915/intel_guc_log.c
>>> @@ -657,8 +657,10 @@ void i915_guc_log_unregister(struct  
>>> drm_i915_private *dev_priv)
>>>          return;
>>>     mutex_lock(&dev_priv->drm.struct_mutex);
>>> +    intel_runtime_pm_get(dev_priv);
>>>      /* GuC logging is currently the only user of Guc2Host interrupts  
>>> */
>>>      gen9_disable_guc_interrupts(dev_priv);
>>> +    intel_runtime_pm_put(dev_priv);
>>>      guc_log_runtime_destroy(&dev_priv->guc);
>>
>> Maybe we should just destroy runtime here, and allow irq to be disabled
>> by intel_uc_fini_hw() which will be called right after. This will also
>> fix the upcoming case when log will not be the only user of Guc irqs.
>>
>> See https://patchwork.freedesktop.org/patch/170390/
>>
>> Michal
> Destroying runtime here may create issues as enabled GuC interrupts may  
> be causing the use of the guc_log_runtime.

Yes, but this should be easy to fix.

> Should we move the i915_driver_unregister post i915_gem_unload?

But then we will have to handle the case when gem was unloaded but
driver will still be in registered state.

Note that as guc log will not be the only user of the guc irqs,
code that disables irq will be removed from this function anyway.

Michal

>>
>>> mutex_unlock(&dev_priv->drm.struct_mutex);
>>>  }