Re: [PATCH v3 6/9] radeon: Switch to arch_phys_wc_add and add amissing ..._del

From: Andy Lutomirski
Date: Thu May 16 2013 - 17:00:57 EST

On Thu, May 16, 2013 at 6:50 AM, Jerome Glisse <j.glisse@xxxxxxxxx> wrote:
> On Wed, May 15, 2013 at 2:22 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
>> On Wed, May 15, 2013 at 7:49 AM, Jerome Glisse <j.glisse@xxxxxxxxx> wrote:
>>> On Tue, May 14, 2013 at 5:35 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
>>>> On Tue, May 14, 2013 at 6:37 AM, Jerome Glisse <j.glisse@xxxxxxxxx> wrote:
>>>>> On Tue, May 14, 2013 at 8:58 AM, Alex Deucher <alexdeucher@xxxxxxxxx> wrote:
>>>>>> On Mon, May 13, 2013 at 7:58 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
>>>>>>> Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
>>>>>>> Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
>>>>>> Reviewed-by: Alex Deucher <alexander.deucher@xxxxxxx>
>>>>> I believe it will break something but we could deal with the fallout
>>>>> once it happens.
>>>> FWIW, I'm running with this code on my machine right now using the
>>>> radeon driver. Everything seems fine. If I build without MTRRs and
>>>> without PAT, though, graphics are slow (as expected). So I think
>>>> everything's okay.
>>>> --Andy
>>> I am worried on p4 where i last see issue with that notably with agp.
>> Do you remember any details? It looks like PAT is enabled on Pentium
>> 4 (i.e. famliy 0xF).
>> --Andy
> No i don't, i think it was some pat errata on those about non real ram
> address and with agp. Memory is fuzzy. I might have time in couple of
> week to plug back my p4 and see how it behave.

Hmm. I couldn't find any PAT errata related to AGP.

Is it possible that the issue was that, if there was no MTRR covering
the AGP aperture, that the mapping ended up as writeback? If so, I
fixed that in this series.

In any case, if you see any problems, please let me know.

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