[Intel-gfx] [PATCH 2/2] drm/i915/bdw: Export workaround data to debugfs

[Chris Wilson]

On Wed, Aug 27, 2014 at 05:44:55PM +0200, Daniel Vetter wrote:
> On Tue, Aug 26, 2014 at 02:44:51PM +0100, Arun Siluvery wrote:
> > The workarounds that are applied are exported to a debugfs file;
> > this is used to verify their state after the test case (reset or
> > suspend/resume etc). This patch is only required to support i-g-t.
> > 
> >  static int gen8_init_workarounds(struct intel_engine_cs *ring)
> >  {
> >  	int ret;
> > +	struct drm_device *dev = ring->dev;
> > +	struct drm_i915_private *dev_priv = dev->dev_private;
> >  
> >  	/*
> >  	 * workarounds applied in this fn are part of register state context,
> >  	 * they need to be re-initialized followed by gpu reset, suspend/resume,
> >  	 * module reload.
> >  	 */
> > +	dev_priv->num_wa_regs = 0;
> > +	memset(dev_priv->intel_wa_regs, 0, sizeof(dev_priv->intel_wa_regs));
> 
> I've dropped this part - we allocate dev_priv already zeroed, so this is
> redundant. And I expect that we'll use this w/a table from other places
> (so not just for render w/a, but also other stuff that can get lost e.g.
> over runtime pm), and then the clearing here could be harmful.

But this is just a debugfs readback, something that userspace can
already do, and does. The w/a table here isn't particularly useful as
is, plus the changes in this patch wrt to writing the registers! still
could really do with some tlc.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre