[PATCH 6.18 203/396] ALSA: lx6464es: fix period byte count for 16-bit streams

6.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Xu Rao <[email protected]>

commit 6437033bffe8bd2af174d139af552d90d40c7ac6 upstream.

The lx6464es driver advertises both 16-bit and packed 24-bit PCM formats,
but lx_trigger_start() and lx_interrupt_request_new_buffer() calculate the
DMA period size as runtime->period_size * runtime->channels * 3.  That is
only correct for the packed 24-bit formats.

For 16-bit streams the driver submits buffers that are 50% larger than the
actual ALSA period and advances the DMA address by the same wrong amount.
For example, with 2 channels, 256 frames and 4 periods, the third buffer
already extends beyond the ALSA buffer and the fourth buffer starts outside
it.

Use snd_pcm_lib_period_bytes() so the byte count matches the runtime
format, channel count and period size.

Fixes: 02bec4904508 ("ALSA: lx6464es - driver for the digigram lx6464es interface")
Cc: [email protected]
Signed-off-by: Xu Rao <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Takashi Iwai <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 sound/pci/lx6464es/lx6464es.c |    5 +----
 sound/pci/lx6464es/lx_core.c  |    5 +----
 2 files changed, 2 insertions(+), 8 deletions(-)

--- a/sound/pci/lx6464es/lx6464es.c
+++ b/sound/pci/lx6464es/lx6464es.c
@@ -402,11 +402,8 @@ static void lx_trigger_start(struct lx64
 
 	int err;
 
-	const u32 channels = substream->runtime->channels;
-	const u32 bytes_per_frame = channels * 3;
-	const u32 period_size = substream->runtime->period_size;
 	const u32 periods = substream->runtime->periods;
-	const u32 period_bytes = period_size * bytes_per_frame;
+	const u32 period_bytes = snd_pcm_lib_period_bytes(substream);
 
 	dma_addr_t buf = substream->dma_buffer.addr;
 	int i;
--- a/sound/pci/lx6464es/lx_core.c
+++ b/sound/pci/lx6464es/lx_core.c
@@ -969,10 +969,7 @@ static int lx_interrupt_request_new_buff
 	const unsigned int is_capture = lx_stream->is_capture;
 	int err;
 
-	const u32 channels = substream->runtime->channels;
-	const u32 bytes_per_frame = channels * 3;
-	const u32 period_size = substream->runtime->period_size;
-	const u32 period_bytes = period_size * bytes_per_frame;
+	const u32 period_bytes = snd_pcm_lib_period_bytes(substream);
 	const u32 pos = lx_stream->frame_pos;
 	const u32 next_pos = ((pos+1) == substream->runtime->periods) ?
 		0 : pos + 1;