[Mesa-dev] [PATCH 19/19] r600g: convert the remnants of VGT state into immediate register writes

[Jerome Glisse]

On Tue, Sep 11, 2012 at 2:29 PM, Marek Olšák <maraeo at gmail.com> wrote:
> On Tue, Sep 11, 2012 at 7:41 PM, Jerome Glisse <j.glisse at gmail.com> wrote:
>> On Tue, Sep 11, 2012 at 1:10 PM, Marek Olšák <maraeo at gmail.com> wrote:
>>> Please provide information about the GPU and the test which locks up. I'd
>>> like to reproduce it. Also please explain what's the cause of the
>>> lockup if you know it (which registers are not emitted in the correct
>>> order and how it can fixed).
>>>
>>> Marek
>>>
>>
>> For instance
>> http://people.freedesktop.org/~glisse/registerposition/lockup-longprim.sh
>>
>> will lockup probably any r6xx/r7xx (definitely rv670 & rv770)
>>
>> I know that the whole vgt register order is picky and that most of
>> them need to be emitted before ta_cntl_aux and before cb/db. But the
>> ordering relative to pa is kind of weird and moving when looking at
>> fglrx.
>
> I tested RS880, which is very similar to RV670, and it didn't hang. I
> can test RV670 later and if there's any issue, I'll fix it. I'd like
> this patch to be fixed instead of dropped, that's why I'm asking and I
> still haven't got a definitive answer how to change the patch, so that
> it can be pushed. Besides that...
>
> Has it ever occured to you that the register ordering is changing in
> fglrx, because the ordering doesn't matter at all, just like Alex
> said, and the closed driver devs wrote it that way because they didn't
> care about the ordering either?

fglrx definitly emit register according to certain grouping. Thing is
there is a bunch of register that are emitted in 2/3 or 4 different
group at most of what i have seen. Otherwise all other register are
_always_ emitted as part of same group with the whole group being
emitted. The issue i have is understanding those register that are
emitted in few different ways and how fglrx choose btw those different
one.

>
> I think the lockups you are seeing on r600-r700 are actually caused by
> something entirely different and it confuses you. See this thread from
> the comment #9 onwards:
> https://bugs.freedesktop.org/show_bug.cgi?id=50655#c9
>
> Marek