On Wed, Jan 28, 2015 at 03:28:56PM +0200, Mika Kuoppala wrote: > Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> writes: > > > On Wed, Jan 28, 2015 at 02:43:25PM +0200, Mika Kuoppala wrote: > >> commit 05a2fb157e44a53c79133805d30eaada43911941 > >> Author: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx> > >> Date: Mon Jan 19 16:20:43 2015 +0200 > >> > >> drm/i915: Consolidate forcewake code > >> > >> introduced domain handling where each domain has it's own posting > >> read registers. This changed the forcewake sequence on 'put' side when > >> there is multiple domains as there would be extra read between the domain > >> puts. Any posting read should be enough to flush all the changes. > >> > >> Do a posting read only once, at the end of the sequence and for > >> the first domain. Like it was before. > >> > >> Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > >> Signed-off-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxx> > > > > fwiw, I would argue that the posting read in _get() is superfluous as we > > will serialise the fw with not only the ack, but any subsequent mmio. > > > > On the _put() side we do want to flush the write so that the hw can > > power down as early as possible. So just kill the posting read from _get > > and otherwise drop the patch. :) > > Yes, both put/get patches should be dropped. I posted a patch removing > the posting read on get side and with your explanations in commit message. > > This all starts to make so much sense that some gen is bound to break ;) IIRC the posting read from same cache line actually fixed real bugs. So I'm a bit worried about dropping them. But I suppose it's possible only the _put side was important for those bugs. -- Ville Syrjälä Intel OTC _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
