On Wed, Nov 08, 2017 at 08:57:52PM +0000, Mark Brown wrote: >On Wed, Nov 08, 2017 at 08:49:55PM +0000, Levin, Alexander (Sasha Levin) wrote: >> From: Jiada Wang <jiada_wang@xxxxxxxxxx> >> >> [ Upstream commit 66459c5a50a787c474b734b586328f7111ab6df0 ] >> >> Previously DMA watermark level is configured to fifosize/2, >> DMA mode can be used only when transfer length can be divided >> by 'watermark level * bpw', which makes DMA mode not pratical. >> >> This patch adjusts watermark level to largest number (no bigger >> than fifosize/2) which can divide 'tranfer length / bpw' for >> each transfer. > >This seems like an optimization not a bug fix... Hm, is it? I read it as "DMA is not being used at all even though we thought we're using it". Yes, the impact is "just" performance, but doesn't it result in quite a significat impact? -- Thanks, Sasha