Re: [RFC 00/11] vb2: Handle user cache hints, allow drivers to choose cache coherency

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

+ Sumit, Rob, Laura and Daniel who have discussed cache optimization with me 
at LPC in the context of dmabuf.

The full patch set can be found at https://www.mail-archive.com/linux-media@vger.kernel.org/msg92120.html

On Tuesday 08 September 2015 13:33:44 Sakari Ailus wrote:
> Hi folks,
> 
> This RFC patchset achieves two main objectives:
> 
> 1. Respects cache flags passed from the user space. As no driver nor
> videobuf2 has (ever?) implemented them, the two flags are replaced by a
> single one (V4L2_BUF_FLAG_NO_CACHE_SYNC) and the two old flags are
> deprecated. This is done since a single flag provides the driver with
> enough information on what to do. (See more info in patch 4.)
> 
> 2. Allows a driver using videobuf2 dma-contig memory type to choose
> whether it prefers coherent or non-coherent CPU access to buffer memory
> for MMAP and USERPTR buffers. This could be later extended to be specified
> by the user, and per buffer if needed.
> 
> Only dma-contig memory type is changed but the same could be done to
> dma-sg as well. I can add it to the set if people are happy with the
> changes to dma-contig.

-- 
Regards,

Laurent Pinchart