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

From: Punit Agrawal
Date: Thu Jun 23 2016 - 08:58:03 EST

Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> writes:

> On 23 June 2016 at 11:55, Punit Agrawal <punit.agrawal@xxxxxxx> wrote:
>> Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> 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@xxxxxxxxxx>
>> 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?