The patch
ASoC: amd: Modified DMA transfer Mechanism for Playback
has been applied to the asoc tree at
https://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.
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Thanks, Mark
From 31c45b3e8d0ecc3a5cbfbf3dfe18adeab2f17a48 Mon Sep 17 00:00:00 2001
From: Vijendar Mukunda Vijendar.Mukunda@amd.com Date: Thu, 9 Nov 2017 12:35:52 -0500 Subject: [PATCH] ASoC: amd: Modified DMA transfer Mechanism for Playback
Before rendering starts, DMA driver copies full buffer valid data to ACP SRAM for the first time, after that ACP SRAM to I2S FIFO DMA will be initiated. After rendering first half of ACP SRAM, IOC will be raised then Audio data will be copied from first half of System Memory to first half of ACP SRAM. Similarly after rendering second half of ACP SRAM, IOC will be raised then Audio Data will be copied from second half of the System Memory to second half of the ACP SRAM in ping-pong way till rendering stops.
Old design introducing latency issues resulting stutter sound observed during playback.
Signed-off-by: Vijendar Mukunda Vijendar.Mukunda@amd.com Signed-off-by: Akshu Agrawal Akshu.Agrawal@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Mark Brown broonie@kernel.org --- sound/soc/amd/acp-pcm-dma.c | 27 +++++---------------------- 1 file changed, 5 insertions(+), 22 deletions(-)
diff --git a/sound/soc/amd/acp-pcm-dma.c b/sound/soc/amd/acp-pcm-dma.c index ef7e98ad960c..9f521a55d610 100644 --- a/sound/soc/amd/acp-pcm-dma.c +++ b/sound/soc/amd/acp-pcm-dma.c @@ -193,8 +193,8 @@ static void set_acp_sysmem_dma_descriptors(void __iomem *acp_mmio, dmadscr[i].xfer_val = 0; if (direction == SNDRV_PCM_STREAM_PLAYBACK) { dma_dscr_idx = PLAYBACK_START_DMA_DESCR_CH12 + i; - dmadscr[i].dest = ACP_SHARED_RAM_BANK_1_ADDRESS + - (size / 2) - (i * (size/2)); + dmadscr[i].dest = ACP_SHARED_RAM_BANK_1_ADDRESS + + (i * (size/2)); dmadscr[i].src = ACP_INTERNAL_APERTURE_WINDOW_0_ADDRESS + (pte_offset * SZ_4K) + (i * (size/2)); switch (asic_type) { @@ -655,9 +655,9 @@ static irqreturn_t dma_irq_handler(int irq, void *arg) valid_irq = true; if (acp_reg_read(acp_mmio, mmACP_DMA_CUR_DSCR_13) == PLAYBACK_START_DMA_DESCR_CH13) - dscr_idx = PLAYBACK_START_DMA_DESCR_CH12; - else dscr_idx = PLAYBACK_END_DMA_DESCR_CH12; + else + dscr_idx = PLAYBACK_START_DMA_DESCR_CH12; config_acp_dma_channel(acp_mmio, SYSRAM_TO_ACP_CH_NUM, dscr_idx, 1, 0); acp_dma_start(acp_mmio, SYSRAM_TO_ACP_CH_NUM, false); @@ -882,23 +882,6 @@ static int acp_dma_prepare(struct snd_pcm_substream *substream) config_acp_dma_channel(rtd->acp_mmio, ACP_TO_I2S_DMA_CH_NUM, PLAYBACK_START_DMA_DESCR_CH13, NUM_DSCRS_PER_CHANNEL, 0); - /* Fill ACP SRAM (2 periods) with zeros from System RAM - * which is zero-ed in hw_params - */ - acp_dma_start(rtd->acp_mmio, SYSRAM_TO_ACP_CH_NUM, false); - - /* ACP SRAM (2 periods of buffer size) is intially filled with - * zeros. Before rendering starts, 2nd half of SRAM will be - * filled with valid audio data DMA'ed from first half of system - * RAM and 1st half of SRAM will be filled with Zeros. This is - * the initial scenario when redering starts from SRAM. Later - * on, 2nd half of system memory will be DMA'ed to 1st half of - * SRAM, 1st half of system memory will be DMA'ed to 2nd half of - * SRAM in ping-pong way till rendering stops. - */ - config_acp_dma_channel(rtd->acp_mmio, SYSRAM_TO_ACP_CH_NUM, - PLAYBACK_START_DMA_DESCR_CH12, - 1, 0); } else { config_acp_dma_channel(rtd->acp_mmio, ACP_TO_SYSRAM_CH_NUM, CAPTURE_START_DMA_DESCR_CH14, @@ -913,7 +896,7 @@ static int acp_dma_prepare(struct snd_pcm_substream *substream) static int acp_dma_trigger(struct snd_pcm_substream *substream, int cmd) { int ret; - u32 loops = 1000; + u32 loops = 4000; u64 bytescount = 0;
struct snd_pcm_runtime *runtime = substream->runtime;