[Intel-gfx] [PATCH 2/2] drm/i915: Reorder media/render reset on g4x

[Mika Kuoppala]

Ville Syrjälä <ville.syrjala at linux.intel.com> writes:

> On Tue, May 16, 2017 at 04:38:01PM +0300, Mika Kuoppala wrote:
>> Chris Wilson <chris at chris-wilson.co.uk> writes:
>> 
>> > Ville found a reference to WaMediaResetBeforeFullReset which we presume
>> > means that we should simply do the media reset first.
>> 
>> Yesterday I reordered the resets but I recall it didnt help.
>> I will retry but regardless yeah resetting media first makes
>> sense.
>> 
>> >
>> > References: https://bugs.freedesktop.org/show_bug.cgi?id=100942
>> > Suggested-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
>> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
>> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
>> > Cc: Mika Kuoppala <mika.kuoppala at intel.com>
>> > ---
>> >  drivers/gpu/drm/i915/intel_uncore.c | 12 ++++++------
>> >  1 file changed, 6 insertions(+), 6 deletions(-)
>> >
>> > diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
>> > index fc3da0a6fdbb..c3d0d81b50e4 100644
>> > --- a/drivers/gpu/drm/i915/intel_uncore.c
>> > +++ b/drivers/gpu/drm/i915/intel_uncore.c
>> > @@ -1504,12 +1504,6 @@ static int g4x_do_reset(struct drm_i915_private *dev_priv, unsigned engine_mask)
>> >  	struct pci_dev *pdev = dev_priv->drm.pdev;
>> >  	int ret;
>> >  
>> > -	pci_write_config_byte(pdev, I915_GDRST,
>> > -			      GRDOM_RENDER | GRDOM_RESET_ENABLE);
>> > -	ret =  wait_for(g4x_reset_complete(pdev), 500);
>> > -	if (ret)
>> > -		goto out;
>> > -
>> >  	/* WaVcpClkGateDisableForMediaReset:ctg,elk */
>> >  	I915_WRITE(VDECCLK_GATE_D, I915_READ(VDECCLK_GATE_D) | VCP_UNIT_CLOCK_GATE_DISABLE);
>> >  	POSTING_READ(VDECCLK_GATE_D);
>> > @@ -1517,11 +1511,17 @@ static int g4x_do_reset(struct drm_i915_private *dev_priv, unsigned engine_mask)
>> >  	pci_write_config_byte(pdev, I915_GDRST,
>> >  			      GRDOM_MEDIA | GRDOM_RESET_ENABLE);
>> >  	ret =  wait_for(g4x_reset_complete(pdev), 500);
>> > +	if (ret)
>> > +		goto out;
>> >
>> 
>> We should restore the WaVcp... state if we fail. Not that it
>> was right to begin with.
>
> I had it that way so that one could figure out which part of the reset
> failed by examining the registers afterwards. If we change that then
> we should add more debug/error prints to let us know exactly what failed.
>

Well with that explanation,
Reviewed-by: Mika Kuoppala <mika.kuoppala at intel.com>

Sadly, the reset can still fail even with this applied.
-Mika

>> 
>> -Mika
>> 
>> >  	/* WaVcpClkGateDisableForMediaReset:ctg,elk */
>> >  	I915_WRITE(VDECCLK_GATE_D, I915_READ(VDECCLK_GATE_D) & ~VCP_UNIT_CLOCK_GATE_DISABLE);
>> >  	POSTING_READ(VDECCLK_GATE_D);
>> >  
>> > +	pci_write_config_byte(pdev, I915_GDRST,
>> > +			      GRDOM_RENDER | GRDOM_RESET_ENABLE);
>> > +	ret =  wait_for(g4x_reset_complete(pdev), 500);
>> > +
>> >  out:
>> >  	pci_write_config_byte(pdev, I915_GDRST, 0);
>> >  	return ret;
>> > -- 
>> > 2.11.0
>
> -- 
> Ville Syrjälä
> Intel OTC