[PATCH] Revert "drm/i915: GFX_MODE Flush TLB Invalidate Mode must be '1' for scanline waits"

[Luis Henriques]

On Tue, Apr 23, 2013 at 05:59:49AM -0600, Tim Gardner wrote:
> On 04/23/2013 02:53 AM, Luis Henriques wrote:
> >On Mon, Apr 22, 2013 at 04:23:17PM -0500, Steve Conklin wrote:
> >>This reverts commit 30ae292ec68402c773ddc8c80f83f7cd84289a39.
> >>
> >>This has been shown to cause GPU hangs
> >>---
> >>  drivers/gpu/drm/i915/intel_ringbuffer.c |    5 -----
> >>  1 file changed, 5 deletions(-)
> >>
> >>diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> >>index c3654ff..fbaa785 100644
> >>--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> >>+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> >>@@ -422,11 +422,6 @@ static int init_render_ring(struct intel_ring_buffer *ring)
> >>  	if (INTEL_INFO(dev)->gen >= 6)
> >>  		I915_WRITE(MI_MODE, GFX_MODE_ENABLE(ASYNC_FLIP_PERF_DISABLE));
> >>
> >>-	/* Required for the hardware to program scanline values for waiting */
> >>-	if (INTEL_INFO(dev)->gen == 6)
> >>-		I915_WRITE(GFX_MODE,
> >>-			   GFX_MODE_ENABLE(GFX_TLB_INVALIDATE_ALWAYS));
> >>-
> >>  	if (IS_GEN7(dev))
> >>  		I915_WRITE(GFX_MODE_GEN7,
> >>  			   GFX_MODE_DISABLE(GFX_TLB_INVALIDATE_ALWAYS) |
> >>--
> >>1.7.9.5
> >>
> >>
> >>--
> >>kernel-team mailing list
> >>kernel-team at lists.ubuntu.com
> >>https://lists.ubuntu.com/mailman/listinfo/kernel-team
> >
> >Comment 99 in bug #1167114 refers to a debian bug that seems to be a
> >duplicate.  And the solution was commit
> >054430e773c9a1e26f38e30156eff02dedfffc17 (fbcon: fix locking harder).
> >Maybe its worth trying a kernel with this fix.
> >
> >(This commit is already in 3.5.y, so I should have already identified
> >it as a possible fix for these bugs... My bad, I've queued it without
> >taking a look at the full context.)
> >
> >Cheers,
> >--
> >Luis
> >
> 
> Is that really related ? It seems like it might be a different bug
> altogether since most of the reporters don't have issues until well
> after boot.

Well, hard to say... the bugs in LP are now really messy and, as Steve
already said, we're almost for sure dealing here with more than one
issue.

So, maybe our best option is to go ahead and revert this commit.  And
probably also the other (5?) we've added last cycle.  Next SRU cycle
we'll have the 054430e773c9a1e26f38e30156eff02dedfffc17 from stable
updates.

Cheers,
--
Luis