[Intel-gfx] [PATCH 19/24] drm/i915: don't enable PM_VEBOX_CS_ERROR_INTERRUPT

[Daniel Vetter]

On Wed, Jun 12, 2013 at 8:19 PM, Ben Widawsky <ben at bwidawsk.net> wrote:
> On Wed, Jun 12, 2013 at 07:18:38PM +0200, Daniel Vetter wrote:
>> On Wed, Jun 12, 2013 at 10:13:41AM -0700, Ben Widawsky wrote:
>> > On Wed, Jun 12, 2013 at 01:37:21PM +0200, Daniel Vetter wrote:
>> > > The code to handle it is broken - there's simply no code to clear CS
>> > > parser errors on gen5+. And behold, for all the other rings we also
>> > > don't enable it!
>> > >
>> > > Leave the handling code itself in place just to be consistent with the
>> > > existing mess though. And in case someone feels like fixing it all up.
>> > >
>> > > This has been errornously enabled in
>> > >
>> > > commit 12638c57f31952127c734c26315e1348fa1334c2
>> > > Author: Ben Widawsky <ben at bwidawsk.net>
>> > > Date:   Tue May 28 19:22:31 2013 -0700
>> > >
>> > >     drm/i915: Enable vebox interrupts
>> > >
>> > > Cc: Damien Lespiau <damien.lespiau at intel.com>
>> > > Cc: Ben Widawsky <ben at bwidawsk.net>
>> > > Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
>> > >
>> > Why not fix the problem instead of just disabling the interrupt? Then
>> > the "existing mess" is justified. It really shouldn't be terribly
>> > difficult to fix it.
>>
>> Haven't seen it proven useful, and I don't want to blow through time just
>> for fun on it. Hangcheck seems to be able to deal with it just fine.
>> -Daniel
> I don't get it. Isn't it just clearing a bit in the handler, vs.
> clearing the flag here?

On a quick Bspec read we'd need to set up per-ring error interrupt
registers, put them to sensible value in them, wire up the interrupt
handling for each ring since ilk+ and then also test it. I really
don't see the point in doing that. The only upshot of all that work is
that if there's an instruction error we'd get an interrupt instead of
waiting for the hangcheck to kick in.

If you insist I can follow-up with a patch to just rip out the
bare-bones handler we have now. Everything else really feels like
wasted effort to me.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch