On Tue, 27 Sep 2011 22:54:01 +0100
Chris Wilson <ch...@chris-wilson.co.uk> wrote:
> On Tue, 27 Sep 2011 12:38:59 -0700, Ben Widawsky <b...@bwidawsk.net> wrote:
> > If we do this we lose the possibility to kick rings, but not reset the
> > GPU (not that I find that terribly useful. If we do this, it does fire a
> > wq event, but I don't see a problem with that for this case.
> >
> > I think I would rather do this:
> > diff --git a/drivers/gpu/drm/i915/i915_irq.c
> > b/drivers/gpu/drm/i915/i915_irq.c
> > index 012732b..803524e 100644
> > --- a/drivers/gpu/drm/i915/i915_irq.c
> > +++ b/drivers/gpu/drm/i915/i915_irq.c
> > @@ -1698,6 +1698,10 @@ void i915_hangcheck_elapsed(unsigned long data)
> > if (dev_priv->hangcheck_count++ > 1) {
> > DRM_ERROR("Hangcheck timer elapsed... GPU hung\n");
> >
> > + /* Save off error state before kicking the rings and
> > + * possibly ruining the GPU state.
> > + */
> > + i915_handle_error(dev, true);
> > if (!IS_GEN2(dev)) {
> > /* Is the chip hanging on a WAIT_FOR_EVENT?
> > * If so we can simply poke the RB_WAIT bit
> > @@ -1717,7 +1721,6 @@ void i915_hangcheck_elapsed(unsigned long data)
> > goto repeat;
> > }
> >
> > - i915_handle_error(dev, true);
> > return;
> > }
> > } else {
>
> Interesting, if we simply call i915_capture_error_state() rather than move
> the i195_handle_error() earlier we do in fact get the best of both worlds.
We can do this except i915_handle_error() is called i915_driver_irq_handler, so
we have to modify that as well. But yeah, I'm fine with that too, though I
don't think it makes much difference either way.
>
> However, it doesn't address Daniel's statement that kick_rings() provoked
> an unrecoverable hang and so we still need to disable that in order to
> save the error-state. The origin of ring-kicking was to try and recover
> from the modesetting/vsync issues, which apart from the outstanding issue
> in intel_crtc_disable() are behind us. (I hope ;-) We shouldn't be relying
> on i915_reset() and i915.reset=0 tends to be either deliberate or an act of
> desparation so I don't see the issue in also preventing ring-kicking with
> the same parameter. Is there an issue I'm overlooking?
No issue, I just feel that this is redundant to hangcheck_enable, so to me at
least, this just adds extra confusion to an already confusing situation. I seem
to be in the minority though.
To me it's:
reset=0, don't ever try to reset
enable_hangcheck=0, don't ever check if we're hung (ie. don't reset or kick)
And now it's
reset=0, don't every try to reset or kick
enabled_hangcheck=0, don't ever check if we're hung (ie. don't reset or kick)
I'd definitely be in favo(u)r of removing the kick_ring() if it isn't really
useful anymore. It has some forcewake race if I remember correctly which I
never bothered to fix.
> -Chris
>
Ben
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