[Intel-gfx] [PATCH 19/19] drm/i915: only enable HWSTAM interrupts on postinstall on ILK+

[Chris Wilson]

On Wed, Apr 02, 2014 at 12:23:51PM +0100, Chris Wilson wrote:
> On Wed, Apr 02, 2014 at 12:21:45PM +0100, Damien Lespiau wrote:
> > On Tue, Apr 01, 2014 at 03:37:27PM -0300, Paulo Zanoni wrote:
> > > From: Paulo Zanoni <paulo.r.zanoni at intel.com>
> > > 
> > > We should only enable interrupts at postinstall.
> > > 
> > > And now on ILK/SNB/IVB/HSW the irq_preinstall and irq_postinstall
> > > functions leave the hardware in the same state.
> > > 
> > > Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> > 
> > Orthogonal note to this patch, I'm wondering why we enable any interrupt
> > reporting in the HW status page, I don't see anywhere we read that
> > information back? Any idea?
> 
> Back in the SNB days, interrupts broke without this piece of magic.

To be more precise, iirc, it was a step towards getting coherent
breadcrumb writes into the HWS. As it turns out, there were more steps
required. Considering that it can now probably be dropped again? Any
takers?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre