[alsa-devel] [PATCH] dma: add support for reporting pause and resume separately
Vinod
vkoul at kernel.org
Mon Jul 9 19:29:37 CEST 2018
On 02-07-18, 15:08, Marek Szyprowski wrote:
> 'cmd_pause' DMA channel capability means that respective DMA engine
> supports both pausing and resuming given DMA channel. However, in some
> cases it is important to know if DMA channel can be paused without the
> need to resume it. This is a typical requirement for proper residue
> reading on transfer timeout in UART drivers. There are also some DMA
> engines with limited hardware, which doesn't really support resuming.
>
> Reporting pause and resume capabilities separately allows UART drivers to
> properly check for the really required capabilities and operate in DMA
> mode also in systems with limited DMA hardware. On the other hand drivers,
> which rely on full channel suspend/resume support, should now check for
> both 'pause' and 'resume' features.
>
> Existing clients of dma_get_slave_caps() have been checked and the only
> driver which rely on proper channel resuming is soc-generic-dmaengine-pcm
> driver, which has been updated to check the newly added capability.
> Existing 'cmd_pause' now only indicates that DMA engine support pausing
> given DMA channel.
Applied after fixing the subsystem name, thanks
--
~Vinod
More information about the Alsa-devel
mailing list