Linux 2.6.39-rc3

[Alex Deucher]

On Mon, Apr 18, 2011 at 11:29 AM, Jerome Glisse <j.glisse at gmail.com> wrote:
> On Mon, Apr 18, 2011 at 11:23 AM, Alex Deucher <alexdeucher at gmail.com> wrote:
>> On Sun, Apr 17, 2011 at 10:09 AM, Joerg Roedel <joro at 8bytes.org> 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.

That's disabled with no_wb=1 as well.

Alex

>
> Cheers,
> Jerome
>