Re: [PATCH 03/10] drm/i915/chv: Enable Render Standby (RC6) for Cheeryview

[Deepak S <deepak.s@linux.intel.com>]

On Monday 28 April 2014 08:15 PM, Daniel Vetter wrote:
> On Mon, Apr 28, 2014 at 05:29:46PM +0300, Imre Deak wrote:
>>> +static void cherryview_setup_pctx(struct drm_device *dev)
>>> +{
>>> +	struct drm_i915_private *dev_priv = dev->dev_private;
>>> +	unsigned long pctx_paddr;
>>> +	struct i915_gtt *gtt = &dev_priv->gtt;
>>> +	u32 pcbr;
>>> +	int pctx_size = 32*1024;
>>> +
>>> +	pcbr = I915_READ(VLV_PCBR);
>>> +	if ((pcbr >> VLV_PCBR_ADDR_SHIFT) == 0) {
>>> +		/*
>>> +		 * From the Gunit register HAS:
>>> +		 * The Gfx driver is expected to program this register and ensure
>>> +		 * proper allocation within Gfx stolen memory.  For example, this
>>> +		 * register should be programmed such than the PCBR range does not
>>> +		 * overlap with other relevant ranges.
>>> +		 */
>>> +		pctx_paddr = (dev_priv->mm.stolen_base + gtt->stolen_size - pctx_size);
>> This area should be reserved.
> We've had a really lengthy discussion internally about the bios-reserved
> chunk in stolen. It was stalled due to (imo unjustified) fear to leak
> information what the bios actually uses this for.
>
> If we need to reserve more of stolen than we currently do we need to pick
> up that approach again instead of adding more bandaids.
> -Daniel

Agreed. Will change accordingly.