Re: [PATCH 30/43] drm/i915: Parametrize and fix SWF registers

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Mon, Oct 12, 2015 at 09:07:17AM -0700, Jesse Barnes wrote:
> On 09/18/2015 10:03 AM, ville.syrjala@linux.intel.com wrote:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > 
> > Parametrize the SWF registers. This also fixes the register offsets,
> > which were mostly garbage in the old defines.
> > 
> > Also save/restore only as many SWF registers that each platform has.
> > 
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_drv.h     |  2 +-
> >  drivers/gpu/drm/i915/i915_reg.h     | 28 +++++++++++------------
> >  drivers/gpu/drm/i915/i915_suspend.c | 45 ++++++++++++++++++++++++++++---------
> >  3 files changed, 50 insertions(+), 25 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> > index 3bf8a9b..3e35e08 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.h
> > +++ b/drivers/gpu/drm/i915/i915_drv.h
> > @@ -1041,7 +1041,7 @@ struct i915_suspend_saved_registers {
> >  	u32 saveMI_ARB_STATE;
> >  	u32 saveSWF0[16];
> >  	u32 saveSWF1[16];
> > -	u32 saveSWF2[3];
> > +	u32 saveSWF3[3];
> >  	uint64_t saveFENCE[I915_MAX_NUM_FENCES];
> >  	u32 savePCH_PORT_HOTPLUG;
> >  	u16 saveGCDGMBUS;
> > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> > index 0cc41e4b..57b9469 100644
> > --- a/drivers/gpu/drm/i915/i915_reg.h
> > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > @@ -4941,20 +4941,20 @@ enum skl_disp_power_wells {
> >  #define I915_LO_DISPBASE(val)	(val & ~DISP_BASEADDR_MASK)
> >  #define I915_HI_DISPBASE(val)	(val & DISP_BASEADDR_MASK)
> >  
> > -/* VBIOS flags */
> > -#define SWF00			(dev_priv->info.display_mmio_offset + 0x71410)
> > -#define SWF01			(dev_priv->info.display_mmio_offset + 0x71414)
> > -#define SWF02			(dev_priv->info.display_mmio_offset + 0x71418)
> > -#define SWF03			(dev_priv->info.display_mmio_offset + 0x7141c)
> > -#define SWF04			(dev_priv->info.display_mmio_offset + 0x71420)
> > -#define SWF05			(dev_priv->info.display_mmio_offset + 0x71424)
> > -#define SWF06			(dev_priv->info.display_mmio_offset + 0x71428)
> > -#define SWF10			(dev_priv->info.display_mmio_offset + 0x70410)
> > -#define SWF11			(dev_priv->info.display_mmio_offset + 0x70414)
> > -#define SWF14			(dev_priv->info.display_mmio_offset + 0x71420)
> > -#define SWF30			(dev_priv->info.display_mmio_offset + 0x72414)
> > -#define SWF31			(dev_priv->info.display_mmio_offset + 0x72418)
> > -#define SWF32			(dev_priv->info.display_mmio_offset + 0x7241c)
> > +/*
> > + * VBIOS flags
> > + * gen2:
> > + * [00:06] alm,mgm
> > + * [10:16] all
> > + * [30:32] alm,mgm
> > + * gen3+:
> > + * [00:0f] all
> > + * [10:1f] all
> > + * [30:32] all
> > + */
> > +#define SWF0(i)	(dev_priv->info.display_mmio_offset + 0x70410 + (i) * 4)
> > +#define SWF1(i)	(dev_priv->info.display_mmio_offset + 0x71410 + (i) * 4)
> > +#define SWF3(i)	(dev_priv->info.display_mmio_offset + 0x72414 + (i) * 4)
> >  
> >  /* Pipe B */
> >  #define _PIPEBDSL		(dev_priv->info.display_mmio_offset + 0x71000)
> > diff --git a/drivers/gpu/drm/i915/i915_suspend.c b/drivers/gpu/drm/i915/i915_suspend.c
> > index 1ccac61..2d91821 100644
> > --- a/drivers/gpu/drm/i915/i915_suspend.c
> > +++ b/drivers/gpu/drm/i915/i915_suspend.c
> > @@ -122,12 +122,24 @@ int i915_save_state(struct drm_device *dev)
> >  	dev_priv->regfile.saveMI_ARB_STATE = I915_READ(MI_ARB_STATE);
> >  
> >  	/* Scratch space */
> > -	for (i = 0; i < 16; i++) {
> > -		dev_priv->regfile.saveSWF0[i] = I915_READ(SWF00 + (i << 2));
> > -		dev_priv->regfile.saveSWF1[i] = I915_READ(SWF10 + (i << 2));
> > +	if (IS_GEN2(dev_priv) && IS_MOBILE(dev_priv)) {
> > +		for (i = 0; i < 7; i++) {
> > +			dev_priv->regfile.saveSWF0[i] = I915_READ(SWF0(i));
> > +			dev_priv->regfile.saveSWF1[i] = I915_READ(SWF1(i));
> > +		}
> > +		for (i = 0; i < 3; i++)
> > +			dev_priv->regfile.saveSWF3[i] = I915_READ(SWF3(i));
> > +	} else if (IS_GEN2(dev_priv)) {
> > +		for (i = 0; i < 7; i++)
> > +			dev_priv->regfile.saveSWF1[i] = I915_READ(SWF1(i));
> > +	} else if (HAS_GMCH_DISPLAY(dev_priv)) {
> > +		for (i = 0; i < 16; i++) {
> > +			dev_priv->regfile.saveSWF0[i] = I915_READ(SWF0(i));
> > +			dev_priv->regfile.saveSWF1[i] = I915_READ(SWF1(i));
> > +		}
> > +		for (i = 0; i < 3; i++)
> > +			dev_priv->regfile.saveSWF3[i] = I915_READ(SWF3(i));
> >  	}
> > -	for (i = 0; i < 3; i++)
> > -		dev_priv->regfile.saveSWF2[i] = I915_READ(SWF30 + (i << 2));
> >  
> >  	mutex_unlock(&dev->struct_mutex);
> >  
> > @@ -156,12 +168,25 @@ int i915_restore_state(struct drm_device *dev)
> >  	/* Memory arbitration state */
> >  	I915_WRITE(MI_ARB_STATE, dev_priv->regfile.saveMI_ARB_STATE | 0xffff0000);
> >  
> > -	for (i = 0; i < 16; i++) {
> > -		I915_WRITE(SWF00 + (i << 2), dev_priv->regfile.saveSWF0[i]);
> > -		I915_WRITE(SWF10 + (i << 2), dev_priv->regfile.saveSWF1[i]);
> > +	/* Scratch space */
> > +	if (IS_GEN2(dev_priv) && IS_MOBILE(dev_priv)) {
> > +		for (i = 0; i < 7; i++) {
> > +			I915_WRITE(SWF0(i), dev_priv->regfile.saveSWF0[i]);
> > +			I915_WRITE(SWF1(i), dev_priv->regfile.saveSWF1[i]);
> > +		}
> > +		for (i = 0; i < 3; i++)
> > +			I915_WRITE(SWF3(i), dev_priv->regfile.saveSWF3[i]);
> > +	} else if (IS_GEN2(dev_priv)) {
> > +		for (i = 0; i < 7; i++)
> > +			I915_WRITE(SWF1(i), dev_priv->regfile.saveSWF1[i]);
> > +	} else if (HAS_GMCH_DISPLAY(dev_priv)) {
> > +		for (i = 0; i < 16; i++) {
> > +			I915_WRITE(SWF0(i), dev_priv->regfile.saveSWF0[i]);
> > +			I915_WRITE(SWF1(i), dev_priv->regfile.saveSWF1[i]);
> > +		}
> > +		for (i = 0; i < 3; i++)
> > +			I915_WRITE(SWF3(i), dev_priv->regfile.saveSWF3[i]);
> >  	}
> > -	for (i = 0; i < 3; i++)
> > -		I915_WRITE(SWF30 + (i << 2), dev_priv->regfile.saveSWF2[i]);
> >  
> >  	mutex_unlock(&dev->struct_mutex);
> >  
> > 
> 
> I think these were added speculatively in the first place.  Maybe we'd
> see a bug on 8xx without these saved & restored, but I wonder if we'd
> see anything else?

It's hard to know what the firmware does with these. IIRC there's a
"driver loaded" bit in there somewhere we perhaps should set to tell
the firmware to stay away.

Oh and I did eventually find the SWF registers for PCH platforms too.
Currently we don't save/restore those at all, so not sure we should
start either.

> 
> Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>

-- 
Ville Syrjälä
Intel OTC
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