The patch
ASoC: Intel: Skylake: Fix DMA position reporting for capture stream
has been applied to the asoc tree at
git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git
All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted.
You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed.
If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced.
Please add any relevant lists and maintainers to the CCs when replying to this mail.
Thanks, Mark
From fdd85a054b850db43c6abe39c1da28b581be5e93 Mon Sep 17 00:00:00 2001
From: Hardik T Shah hardik.t.shah@intel.com Date: Fri, 24 Mar 2017 23:10:32 +0530 Subject: [PATCH] ASoC: Intel: Skylake: Fix DMA position reporting for capture stream
As per hardware recommendation, for every capture stream completion following operations need to be done in order to reflect the actual data that is received in position buffer.
1. Wait for 20us before reading the DMA position in buffer once the interrupt is generated for stream completion. 2. Read any of the register to flush the DMA position value. This is dummy read operation.
Signed-off-by: Dharageswari R dharageswari.r@intel.com Signed-off-by: Hardik T Shah hardik.t.shah@intel.com Signed-off-by: Jeeja KP jeeja.kp@intel.com Acked-by: Vinod Koul vinod.koul@intel.com Signed-off-by: Mark Brown broonie@kernel.org --- sound/soc/intel/skylake/skl-pcm.c | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-)
diff --git a/sound/soc/intel/skylake/skl-pcm.c b/sound/soc/intel/skylake/skl-pcm.c index ef440d8629e8..1823197c15c8 100644 --- a/sound/soc/intel/skylake/skl-pcm.c +++ b/sound/soc/intel/skylake/skl-pcm.c @@ -21,6 +21,7 @@
#include <linux/pci.h> #include <linux/pm_runtime.h> +#include <linux/delay.h> #include <sound/pcm_params.h> #include <sound/soc.h> #include "skl.h" @@ -1063,13 +1064,31 @@ static snd_pcm_uframes_t skl_platform_pcm_pointer * HAD space reflects the actual data that is transferred. * Use the position buffer for capture, as DPIB write gets * completed earlier than the actual data written to the DDR. + * + * For capture stream following workaround is required to fix the + * incorrect position reporting. + * + * 1. Wait for 20us before reading the DMA position in buffer once + * the interrupt is generated for stream completion as update happens + * on the HDA frame boundary i.e. 20.833uSec. + * 2. Read DPIB register to flush the DMA position value. This dummy + * read is required to flush DMA position value. + * 3. Read the DMA Position-in-Buffer. This value now will be equal to + * or greater than period boundary. */ - if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) + + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) { pos = readl(ebus->bus.remap_addr + AZX_REG_VS_SDXDPIB_XBASE + (AZX_REG_VS_SDXDPIB_XINTERVAL * hdac_stream(hstream)->index)); - else + } else { + udelay(20); + readl(ebus->bus.remap_addr + + AZX_REG_VS_SDXDPIB_XBASE + + (AZX_REG_VS_SDXDPIB_XINTERVAL * + hdac_stream(hstream)->index)); pos = snd_hdac_stream_get_pos_posbuf(hdac_stream(hstream)); + }
if (pos >= hdac_stream(hstream)->bufsize) pos = 0;