Re: [PATCH] lib/scatterlist: Provide a DMA page iterator

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Tue, Jan 15, 2019 at 03:24:55PM +0100, Christian König wrote:
> Yeah, indeed. Bounce buffers are an absolute no-go for GPUs.
>
> If the DMA API finds that a piece of memory is not directly accessible by 
> the GPU we need to return an error and not try to use bounce buffers behind 
> the surface.
>
> That is something which always annoyed me with the DMA API, which is 
> otherwise rather cleanly defined.

That is exactly what I want to fix with my series to make
DMA_ATTR_NON_CONSISTENT more useful and always available:

https://lists.linuxfoundation.org/pipermail/iommu/2018-December/031985.html

With that you allocate the memory using dma_alloc_attrs with
DMA_ATTR_NON_CONSISTENT, and use dma_sync_single_* to transfer
ownership to the cpu and back to the device, with a gurantee that
there won't be any bouncing.  So far the interest by the parties that
requested the feature has been rather lacklustre, though.
_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/dri-devel




[Index of Archives]     [Linux DRI Users]     [Linux Intel Graphics]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]
  Powered by Linux