On 2019/7/18 上午11:35, Pierre-Louis Bossart wrote:
On 7/17/19 10:11 PM, Keyon Jie wrote:
From: Marcin Rajwa <marcin.rajwa@xxxxxxxxxxxxxxx>
In some cases, FW might need to use the host_period_bytes field to
synchronize the DMA copying (with host side) but the driver does not
it's your right to edit my suggested wording, but the notion of
'synchronization' is far from clear. it's my understanding that the
host_period_bytes defines the DMA transfer size requested by the
firmware, which isn't a value that matters to the host except for rewind
usages.
Hi Pierre, here the host_period_bytes is requested by host, FW has its
own period size, and DMA will transfer data in FW buffer period size. It
works like this:
FW buffer[period 0, period 1, ...] <==> DMA <==> host/alsa
buffer[host_period 0, host_priod 1, ...]
We need this host_preiod_bytes information in FW to do fast
draining(e.g. record 2 seconds data within 10ms) in mmap capture, we are
slowing down the draining in smaller host_period_bytes cases, otherwise,
arecord can't read the buffer in time and overrun will happen.
Maybe the wording "synchronize" here is inaccurate, how about something
like this:
"FW might need to use the host_period_bytes field to configure and
control the DMA copying speed but the driver does not..."
need any position information returned over the IPC channel by the
firmware. The current IPC definition prevents this capability, so add
new field.
Signed-off-by: Marcin Rajwa <marcin.rajwa@xxxxxxxxxxxxxxx>
Signed-off-by: Keyon Jie <yang.jie@xxxxxxxxxxxxxxx>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@xxxxxxxxxxxxxxx>
---
include/sound/sof/stream.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/sound/sof/stream.h b/include/sound/sof/stream.h
index 643f175cb479..06af4ecb2584 100644
--- a/include/sound/sof/stream.h
+++ b/include/sound/sof/stream.h
@@ -83,10 +83,10 @@ struct sof_ipc_stream_params {
uint16_t sample_valid_bytes;
uint16_t sample_container_bytes;
- /* for notifying host period has completed - 0 means no period
IRQ */
uint32_t host_period_bytes;
+ uint32_t no_position_ipc; /* 1 means no IPC for position upadte */
typo: update
OK, thanks, another update version needed for it.
Thanks,
~Keyon
- uint32_t reserved[2];
+ uint16_t reserved[3];
uint16_t chmap[SOF_IPC_MAX_CHANNELS]; /**< channel map -
SOF_CHMAP_ */
} __packed;
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