Subject: Re: linux-next: build failure after merge of the drm tree

From: Christoph Hellwig <[email-masked]>
Date: Mon, 28 Sep 2020 13:34:15 +0200

On Mon, Sep 28, 2020 at 12:15:56PM +0200, Paul Cercueil wrote:
> Hi Christoph,
>
> Le lun. 28 sept. 2020 à 8:04, Christoph Hellwig <[email-masked]> a écrit :
>> On Mon, Sep 28, 2020 at 01:54:05PM +1000, Stephen Rothwell wrote:
>>>  Hi all,
>>>
>>>  After merging the drm tree, today's linux-next build (x86_64 
>>> allmodconfig)
>>>  failed like this:
>>
>> The driver needs to switch do dma_alloc_noncoherent + dma_sync_single*
>> like the other drivers converted in the dma tree.  Paul, let me know if
>> you have any questions.
>
> I don't dma_alloc* anything, DRM core does. I use the 
> DMA_ATTR_NON_CONSISTENT attr with dma_mmap_attrs(). Is there a replacement 
> for that?

dma_mmap_attrs can only be used on allocations from dma_mmap_attrs with
the same attrs.  As there is no allocation using DMA_ATTR_NON_CONSISTENT
in the drm core, something looks very fishy here.

Where does the allocation you try to mmap come from?  All the allocations
in drivers/gpu/drm/drm_gem_cma_helper.c seems to use dma_alloc_wc (aka
dma_allloc_attrs with the DMA_ATTR_WRITE_COMBINE flag).