Re: [Intel-gfx] [PATCH] drm/i915: Check for driver readyness before handling an underrun interrupt

[Jani Nikula <jani.nikula@linux.intel.com>]

On Fri, 27 Feb 2015, Jani Nikula <jani.nikula@linux.intel.com> wrote:
> On Thu, 26 Feb 2015, Chris Wilson <chris@chris-wilson.co.uk> wrote:
>> When we takeover from the BIOS and install our interrupt handler, the
>> BIOS may have left us a few surprises in the form of spontaneous
>> interrupts. (This is especially likely on hardware like 965gm where
>> display fifo underruns are continuous and the GMCH cannot filter that
>> interrupt souce.) As we enable our IRQ early so that we can use it
>> during hardware probing, our interrupt handler must be prepared to
>> handle a few sources prior to being fully configured. As such, we need
>> to add a simple is-ready check prior to dereferencing our KMS state for
>> reporting underruns.
>>
>> Reported-by: Rob Clark <rclark@redhat.com>
>> Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1193972
>
> "You are not authorized to access bug #1193972. To see this bug, you
> must first log in to an account with the appropriate permissions."
>
> Meh.

Pushed to drm-intel-fixes, thanks for the patch and review. If someone
both cares and has access to the bugzilla, please update it.

BR,
Jani.

>
>> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
>> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
>> Cc: stable@vger.kernel.org
>> ---
>>  drivers/gpu/drm/i915/intel_fifo_underrun.c | 18 +++++++-----------
>>  1 file changed, 7 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_fifo_underrun.c b/drivers/gpu/drm/i915/intel_fifo_underrun.c
>> index 04e248dd2259..f2fd992e3cd8 100644
>> --- a/drivers/gpu/drm/i915/intel_fifo_underrun.c
>> +++ b/drivers/gpu/drm/i915/intel_fifo_underrun.c
>> @@ -282,16 +282,6 @@ bool intel_set_cpu_fifo_underrun_reporting(struct drm_i915_private *dev_priv,
>>  	return ret;
>>  }
>>  
>> -static bool
>> -__cpu_fifo_underrun_reporting_enabled(struct drm_i915_private *dev_priv,
>> -				      enum pipe pipe)
>> -{
>> -	struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe];
>> -	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
>> -
>> -	return !intel_crtc->cpu_fifo_underrun_disabled;
>> -}
>> -
>>  /**
>>   * intel_set_pch_fifo_underrun_reporting - set PCH fifo underrun reporting state
>>   * @dev_priv: i915 device instance
>> @@ -352,9 +342,15 @@ bool intel_set_pch_fifo_underrun_reporting(struct drm_i915_private *dev_priv,
>>  void intel_cpu_fifo_underrun_irq_handler(struct drm_i915_private *dev_priv,
>>  					 enum pipe pipe)
>>  {
>> +	struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe];
>> +
>> +	/* We may be called too early in init, thanks BIOS! */
>> +	if (crtc == NULL)
>> +		return;
>> +
>>  	/* GMCH can't disable fifo underruns, filter them. */
>>  	if (HAS_GMCH_DISPLAY(dev_priv->dev) &&
>> -	    !__cpu_fifo_underrun_reporting_enabled(dev_priv, pipe))
>> +	    !to_intel_crtc(crtc)->cpu_fifo_underrun_disabled)
>>  		return;
>>  
>>  	if (intel_set_cpu_fifo_underrun_reporting(dev_priv, pipe, false))
>> -- 
>> 2.1.4
>>
>> _______________________________________________
>> Intel-gfx mailing list
>> Intel-gfx@lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
> -- 
> Jani Nikula, Intel Open Source Technology Center

-- 
Jani Nikula, Intel Open Source Technology Center