Re: [RFC PATCH] drm/nouveau/fb/nv50: set DMA mask before mapping scratch page

From	Ard Biesheuvel <ard.biesheuvel@linaro.org>
Newsgroups	linux.kernel
Subject	Re: [RFC PATCH] drm/nouveau/fb/nv50: set DMA mask before mapping scratch page
Date	2016-06-23 12:10 +0200
Message-ID	<rN9K9-8oP-3@gated-at.bofh.it> (permalink)
References	<rM6EF-8f1-7@gated-at.bofh.it> <rN9At-86a-7@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 23 June 2016 at 11:55, Punit Agrawal <punit.agrawal@arm.com> wrote:
> Ard Biesheuvel <ard.biesheuvel@linaro.org> writes:
>
>> The 100c08 scratch page is mapped using dma_map_page() before the TTM
>> layer has had a chance to set the DMA mask. This means we are still
>> running with the default of 32 when this code executes, and this causes
>> problems for platforms with no memory below 4 GB (such as AMD Seattle)
>>
>> So move the dma_map_page() to the .init hook, and set the streaming DMA
>> mask based on the MMU subdev parameters before performing the call.
>>
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>
> Hi Ard,
>
> Thanks for posting this patch.
>
> With the patch, I am able to see console output on a screen attached to
> the NVS 300 PCIe card in an AMD Seattle system. It was failing with
> a message similar to what you've posted below.
>

Thanks for the report. May I take it as a tested-by?

> For some reason, X refuses to start up but that, I think, is a problem
> with my userspace setup.
>

Good to know that you are attempting the same thing. We should take
this offline, but I'd like to compare notes regarding the Xorg
problems that you are experiencing.

Regards,
Ard.

Thread

[RFC PATCH] drm/nouveau/fb/nv50: set DMA mask before mapping scratch page Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2016-06-20 14:40 +0200
  Re: [RFC PATCH] drm/nouveau/fb/nv50: set DMA mask before mapping scratch page Punit Agrawal <punit.agrawal@arm.com> - 2016-06-23 12:00 +0200
    Re: [RFC PATCH] drm/nouveau/fb/nv50: set DMA mask before mapping  scratch page Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2016-06-23 12:10 +0200
      Re: [RFC PATCH] drm/nouveau/fb/nv50: set DMA mask before mapping scratch page Punit Agrawal <punit.agrawal@arm.com> - 2016-06-23 15:00 +0200

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