On Wednesday 28 of August 2013 09:06:27 Linus Walleij wrote:
On Sun, Aug 11, 2013 at 7:59 PM, Tomasz Figa tomasz.figa@gmail.com
wrote:
The legacy S3C-DMA API required every period of a cyclic buffer to be queued separately. After conversion of Samsung ASoC to Samsung DMA wrappers somebody made an assumption that the same is needed for DMA engine API, which is not true.
In effect, Samsung ASoC DMA code was queuing the whole cyclic buffer
multiple times with a shift of one period per iteration, leading to: a) severe memory waste - up to 13x times more DMA transfer descriptors
are allocated than needed,b) possible memory corruption, because further cyclic buffers were out
of the original buffers, due to the offset.This patch fixes this problem by making the legacy S3C-DMA API use the same semantics as DMA engine (the whole cyclic buffer is enqueued at once) and modifying users of Samsung DMA wrappers in cyclic mode to behave appropriately.
Signed-off-by: Tomasz Figa tomasz.figa@gmail.com Acked-by: Linus Walleij linus.walleij@linaro.org
If patch 1 thru 9 are uncontroversial now, maybe Vinod can apply these for v3.12 so we can get less noise and risk of collissions in the next merge window?
Just an idea.
That would be nice, leaving only Samsung-specific patches for the next merge window.
(That would be patches 1 to 8, though, as 9 is a patch for ASoC that could be picked up by Mark Brown independently.)
Best regards, Tomasz