[Intel-gfx] drm/i915 4.5/4.6 stable backport request for CHV

[Peter Frühberger]

Hi guys,

2016-06-06 11:32 GMT+02:00 Ville Syrjälä <ville.syrjala at linux.intel.com>:

> On Sat, Jun 04, 2016 at 02:06:58PM -0700, Greg KH wrote:
> > On Fri, May 27, 2016 at 11:30:30AM +0300, ville.syrjala at linux.intel.com
> wrote:
> > > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > >
> > > Several nasty i915 regressions affecting CHV slipped through
> > > to 4.5 and 4.6.
> > >
> > > The first fix we want in 4.5 and 4.6 is
> > > commit caed361d83b2 ("drm/i915: Fix watermarks for VLV/CHV")
> > > It won't cherry-pick cleanly to either one, so I've included conflict
> > > free versions for both. This one fixes display FIFO underruns that can
> > > lead to the screen totally blanking out.
> >
> > Now applied, thanks.
> >
> > > The other one I'd like to have in 4.6 is
> > > commit 9f6151c90390 ("drm/i915: Pass the correct crtc state to
> .update_plane()")
> > > which avoids a totally corrupted display in some cases.
> >
> > Now applied.
> >
> > > And the third on is a bit more annoying. The regression is caused by
> > > commit 9dbaab56ac09 ("drm/i915: Exit cherryview_irq_handler() after
> one pass")
> > > which I though we had prevented from getting out on its own, but turns
> > > out I was wrong. It basically makes the GPU unusable, so we do need to
> > > fix it somehow. The simple solution would be to revert it in 4.6 only.
> > > The more complicated solution is to backport the proper fix, which more
> > > or less requires the following set of commits [1], which is maybe a bit
> > > too much for stable. I could try to trim it a bit perhaps, but then we
> > > start to enter the territory of untested code which I don't
> particularly
> > > like. Let me know what you think.
> > >
> > > [1]
> > >  1e1cace942ef ("drm/i915: Eliminate loop from VLV irq handler")
> > >  a5e485a95c9c ("drm/i915: Clear VLV_IER around irq processing")
> > >  4a0a0202b023 ("drm/i915: Clear VLV_MASTER_IER around irq processing")
> > >  7ce4d1f2730f ("drm/i915: Clear VLV_IIR after PIPESTAT")
> > >  34c7b8a7b8b5 ("drm/i915: Set up VLV_MASTER_IER consistently")
> > >  e5328c43d46e ("drm/i915: Use GEN8_MASTER_IRQ_CONTROL consistently")
> > >  71b8b41d5b35 ("drm/i915: Move DPINVGTT setup to
> vlv_display_irq_reset()")
> > >  6b7eafc1b43d ("drm/i915: Warn if irq_mask isn't ~0 during vlv/cvh
> display irq postinstall")
> > >  9ab981f22bef ("drm/i915: Use GEN5_IRQ_INIT() in
> vlv_display_irq_postinstall()")
> > >  d6c698035892 ("drm/i915: Clear display interrupt before enabling when
> turning on the power well")
> > >  8bb613068a63 ("drm/i915: Move vlv/chv display irq code to a more
> logical place")
> > >  9918271efc7a ("drm/i915: Skip display irq setup if display irqs
> aren't flagged as enabled")
> > >  ad22d10654ea ("drm/i915: Fix up vlv/chv display irq setup")
> > >  93de68f94081 ("drm/i915: Remove "VLV magic" from irq setup")
> >
> > I think reverting that one patch for 4.6 makes more sense than adding
> > all of these patches.  I'll do that if you want me to.
>
> That works for me. Thanks.
>
> --
> Ville Syrjälä
> Intel OTC


Sorry for bothering you. Will the revert make it into 4.6.3? Without it BSW
on 4.6 is not really usable.

Thanks much in advance
Peter



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