Re: Linux 2.6.39-rc3

[Jerome Glisse]

On Mon, Apr 18, 2011 at 11:23 AM, Alex Deucher <alexdeucher@xxxxxxxxx> wrote:
> On Sun, Apr 17, 2011 at 10:09 AM, Joerg Roedel <joro@xxxxxxxxxx> wrote:
>> On Sat, Apr 16, 2011 at 02:54:04PM -0400, Jerome Glisse wrote:
>>
>>> If you want to go the printk way you can add printk before each test
>>> ring_test, ib_test in r600.c this 2 functions are the own that might
>>> trigger the first GPU gart activities.
>>
>> Okay, I found the place in source that triggers this. It happens in the
>> function r600_ib_test. The interesting thing is that not the ib-command
>> itself is responsible but the fence that is emitted afterwards (proved
>> by removing the fence command, where the problem went away).
>> I don't know enough about the command semantics to make a guess what
>> goes wrong there. But maybe you GPU folks have an idea?
>>
>
> I can't think of anything off hand.  It might be worth disabling the
> call to r600_ib_test() in r600_init() and then seeing if you get any
> errors when the fences are used later on when X starts or just at that
> point in the module load sequence.  What's odd is that when you tested
> radeon.no_wb=1 you got the same behavior as that disables shadowing of
> fence writes to gpu gart mem, so it wouldn't be writing to memory in
> that case.
>
> Alex
>

It might be the irq ring write that is faulty.

Cheers,
Jerome
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