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Subject: Re: AMD graphics performance regression in 4.15 and later
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From:   =?UTF-8?Q?Christian_K=c3=b6nig?= <ckoenig.leichtzumerken@gmail.com>
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Date:   Tue, 10 Apr 2018 08:48:04 +0200
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Am 09.04.2018 um 17:17 schrieb Jean-Marc Valin:
> On 04/09/2018 05:42 AM, Christian König wrote:
>> Backporting all the detection logic is to invasive, but you could just
>> go into drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c and forcefull use the
>> other code path.
>>
>> Just look out for "#ifdef CONFIG_SWIOTLB" checks and disable those.
> Do you mean just taking the 4.15 code as is and replacing
> "#ifdef CONFIG_SWIOTLB" with "#if 0" in
> drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c or are you talking about using a
> different version of drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c ?

Yes, exactly. The code then won't work any more on some ARMs or systems 
with more than 1TB of memory, but I don't think you care about that :)

Christian.

>
> 	Jean-Marc
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