Re: [PATCH 6/7] misc: bcm-vk: add Broadcom Valkyrie driver

From: Arnd Bergmann
Date: Tue Aug 27 2019 - 10:15:14 EST

On Thu, Aug 22, 2019 at 9:25 PM Scott Branden
<scott.branden@xxxxxxxxxxxx> wrote:
> Add Broadcom Valkyrie driver offload engine.
> This driver interfaces to the Valkyrie PCIe offload engine to perform
> should offload functions as video transcoding on multiple streams
> in parallel. Valkyrie device is booted from files loaded using
> request_firmware_into_buf mechanism. After booted card status is updated
> and messages can then be sent to the card.
> Such messages contain scatter gather list of addresses
> to pull data from the host to perform operations on.
> Signed-off-by: Scott Branden <scott.branden@xxxxxxxxxxxx>
> Signed-off-by: Desmond Yan <desmond.yan@xxxxxxxxxxxx>
> Signed-off-by: James Hu <>

Can you explain the decision to make this is a standalone misc driver
rather than hooking into the existing framework in drivers/media?

There is an existing interface that looks like it could fit the hardware
in include/media/v4l2-mem2mem.h. Have you considered using that?

There is also support for video transcoding using GPUs in
driver/gpu/drm/, that could also be used in theory, though it sounds
like a less optimal fit.