linux-kernel - Re: [PATCH 2/2] nouveau: Acknowledge HPD irq in handler, not bottom half

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Date:	Wed, 10 Nov 2010 23:55:30 +0100
From:	Maarten Maathuis <madman2003@...il.com>
To:	Andrew Lutomirski <luto@....edu>
Cc:	bskeggs@...hat.com, linux-kernel@...r.kernel.org,
	dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH 2/2] nouveau: Acknowledge HPD irq in handler, not bottom half

On Wed, Nov 10, 2010 at 11:51 PM, Andrew Lutomirski <luto@....edu> wrote:
> On Wed, Nov 10, 2010 at 5:35 PM, Ben Skeggs <bskeggs@...hat.com> wrote:
>> On Wed, 2010-11-10 at 17:25 -0500, Andrew Lutomirski wrote:
>>> On Wed, Nov 10, 2010 at 5:10 PM, Ben Skeggs <bskeggs@...hat.com> wrote:
>>> > On Wed, 2010-11-10 at 16:32 -0500, Andy Lutomirski wrote:
>>> >> The old code generated an interrupt storm bad enough to completely
>>> >> take down my system.
>>> >>
>>> >> This only fixes the bits that are defined nouveau_regs.h.  Newer hardware
>>> >> uses another register that isn't described, and I don't have that hardware
>>> >> to test.
>>> > Thanks for looking at this.  I'll take a closer look at the problem
>>> > today and see what I can come up with too, that'll work with the newer
>>> > hardware too.
>>>
>>> It should be as simple as adding an hpd1 field to the hpd_state and
>>> making exactly the same change.  (It would be nice to put the register
>>> definitions into nouveau_regs.h as well -- I didn't really want to
>>> muck around with a bunch of magic numbers that I can't test.)
>> Yes, it is.  I can confirm the problem on another card, but it doesn't
>> actually cause any crashes here.  If you can rework the patch to support
>> the newer chips too, that'd be great.
>>
>> As for magic numbers, the register names for those regs are wrong
>> anyway.  The joy of reverse-engineering the support.  It doesn't really
>> matter if you want to stick to them or go back to "magic" numbers.
>
> That explains why INTR and CTRL seemed backwards :)  I'll leave the
> magic numbers for the 0xe07? stuff.

Perhaps remove the bad definitions from the reg file, or rename them
to UNKsomething?

>
> Also, I accidentally dropped the "& enabled_bits" part -- I'll put that back.
>
> Patch to follow after I boot and test it here.
>
> --Andy
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> dri-devel@...ts.freedesktop.org
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