PowerPC agpmode issues

[Herminio Hernandez, Jr.]

I have already applied his patches on my PowerBook running Jessie to get
accelerated graphics. However they are only a work around and not a real
fix so they will be committed to mesa.

On Fri, Feb 5, 2016 at 8:44 AM, Mike <michael.heltne at gmail.com> wrote:

> Herminio,
>
> Ok, take a look at this.
> https://github.com/threader/mesa-11.1.1-ppc-r300-debian or if on stable
> maybe this is more fitting
> https://github.com/threader/mesa-10.6.3-ppc-r300-debian - this only fixes
> the issue for r300 on powerpc though.
>
> On 5 February 2016 at 14:32, Herminio Hernandez Jr. <
> herminio.hernandezjr at gmail.com> wrote:
>
>> I have been experiencing the same thing with my iBook and PowerBook.
>>
>> Sent from my iPhone
>>
>> On Feb 4, 2016, at 8:47 PM, Mike <michael.heltne at gmail.com> wrote:
>>
>> Hi.
>> Managed to get the Radeon R300 running on mesa 11.1.1 with an old 2013
>> patch from Michel Dànzer, next problem is of course enabling agpmode,
>> running with pci-mode with radeon.agpmode=-1 works, but is of course slow,
>> and seems to load the cpu a lot.
>>
>> Upon initial investigation i could not initially believe agp could be
>> this this broken for this long, until i found this.
>>  "committed with Ben Skeggs on Feb 26, 2013"
>>
>> https://github.com/DespairFactor/bullhead/commit/650e1203c11354ba84d69ba445abc0efcfe3890a
>>
>> http://lxr.free-electrons.com/source/drivers/gpu/drm/nouveau/nouveau_agp.c?v=4.2
>> #ifdef __powerpc__
>> /* Disable AGP by default on all PowerPC machines for
>> * now -- At least some UniNorth-2 AGP bridges are
>> * known to be broken: DMA from the host to the card
>> * works just fine, but writeback from the card to the
>> * host goes straight to memory untranslated bypassing
>> * the GATT somehow, making them quite painful to deal
>> * with...
>> */
>> if (nouveau_agpmode == -1)
>> return false;
>> #endif
>>
>>  and now later this:
>>
>> https://github.com/torvalds/linux/blob/master/drivers/gpu/drm/nouveau/nvkm/subdev/pci/agp.c
>> #ifdef __powerpc__
>> /* Disable AGP by default on all PowerPC machines for now -- At
>> * least some UniNorth-2 AGP bridges are known to be broken:
>> * DMA from the host to the card works just fine, but writeback
>> * from the card to the host goes straight to memory
>> * untranslated bypassing that GATT somehow, making them quite
>> * painful to deal with...
>> */
>> mode = 0;
>> #endif
>>
>> All seems to point to serious issues had around the time of change to ums
>> to kms and a serious regression hitting the linux kernel? No?
>>
>> Cheers
>> -Mike
>>
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>>
>>
>
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