Re: [PATCH v2] drm/xen-front: Make shmem backed display buffer coherent

[Oleksandr Andrushchenko]

On 1/16/19 8:30 AM, Gerd Hoffmann wrote:
>    Hi,
>
>> +	if (!dma_map_sg(dev->dev, xen_obj->sgt->sgl, xen_obj->sgt->nents,
>> +			DMA_BIDIRECTIONAL)) {
>> +		ret = -EFAULT;
>> +		goto fail_free_sgt;
>> +	}
> Hmm, so it seems the arm guys could not come up with a suggestion how to
> solve that one in a better way.  Ok, lets go with this then.
>
> But didn't we agree that this deserves a comment exmplaining the purpose
> of the dma_map_sg() call is to flush caches and that there is no actual
> DMA happening here?
My bad, will add the comment
> cheers,
>    Gerd
>
Thank you,
Oleksandr