[PATCH 4.19 28/36] Revert "ALSA: usb-audio: Improve frames size computation"

Greg Kroah-Hartman
2020-07-07T15:34:08Z

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 2d50acd7dbd0682a56968ad9551341d7fc5b6eaf which is
commit f0bd62b64016508938df9babe47f65c2c727d25c upstream.

It causes a number of reported issues and a fix for it has not hit
Linus's tree yet. Revert this to resolve those problems.

Cc: Alexander Tsoy <alexander@tsoy.me>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Hans de Goede <jwrdegoede@fedoraproject.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
sound/usb/card.h | 4 ----
sound/usb/endpoint.c | 43 +++++--------------------------------------
sound/usb/endpoint.h | 1 -
sound/usb/pcm.c | 2 --
4 files changed, 5 insertions(+), 45 deletions(-)

--- a/sound/usb/card.h
+++ b/sound/usb/card.h
@@ -83,10 +83,6 @@ struct snd_usb_endpoint {
dma_addr_t sync_dma; /* DMA address of syncbuf */

unsigned int pipe; /* the data i/o pipe */
- unsigned int framesize[2]; /* small/large frame sizes in samples */
- unsigned int sample_rem; /* remainder from division fs/fps */
- unsigned int sample_accum; /* sample accumulator */
- unsigned int fps; /* frames per second */
unsigned int freqn; /* nominal sampling rate in fs/fps in Q16.16 format */
unsigned int freqm; /* momentary sampling rate in fs/fps in Q16.16 format */
int freqshift; /* how much to shift the feedback value to get Q16.16 */
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -137,12 +137,12 @@ int snd_usb_endpoint_implicit_feedback_s

/*
* For streaming based on information derived from sync endpoints,
- * prepare_outbound_urb_sizes() will call slave_next_packet_size() to
+ * prepare_outbound_urb_sizes() will call next_packet_size() to
* determine the number of samples to be sent in the next packet.
*
- * For implicit feedback, slave_next_packet_size() is unused.
+ * For implicit feedback, next_packet_size() is unused.
*/
-int snd_usb_endpoint_slave_next_packet_size(struct snd_usb_endpoint *ep)
+int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep)
{
unsigned long flags;
int ret;
@@ -159,29 +159,6 @@ int snd_usb_endpoint_slave_next_packet_s
return ret;
}

-/*
- * For adaptive and synchronous endpoints, prepare_outbound_urb_sizes()
- * will call next_packet_size() to determine the number of samples to be
- * sent in the next packet.
- */
-int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep)
-{
- int ret;
-
- if (ep->fill_max)
- return ep->maxframesize;
-
- ep->sample_accum += ep->sample_rem;
- if (ep->sample_accum >= ep->fps) {
- ep->sample_accum -= ep->fps;
- ret = ep->framesize[1];
- } else {
- ret = ep->framesize[0];
- }
-
- return ret;
-}
-
static void retire_outbound_urb(struct snd_usb_endpoint *ep,
struct snd_urb_ctx *urb_ctx)
{
@@ -226,8 +203,6 @@ static void prepare_silent_urb(struct sn

if (ctx->packet_size[i])
counts = ctx->packet_size[i];
- else if (ep->sync_master)
- counts = snd_usb_endpoint_slave_next_packet_size(ep);
else
counts = snd_usb_endpoint_next_packet_size(ep);

@@ -912,17 +887,10 @@ int snd_usb_endpoint_set_params(struct s
ep->maxpacksize = fmt->maxpacksize;
ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);

- if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_FULL) {
+ if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_FULL)
ep->freqn = get_usb_full_speed_rate(rate);
- ep->fps = 1000;
- } else {
+ else
ep->freqn = get_usb_high_speed_rate(rate);
- ep->fps = 8000;
- }
-
- ep->sample_rem = rate % ep->fps;
- ep->framesize[0] = rate / ep->fps;
- ep->framesize[1] = (rate + (ep->fps - 1)) / ep->fps;

/* calculate the frequency in 16.16 format */
ep->freqm = ep->freqn;
@@ -981,7 +949,6 @@ int snd_usb_endpoint_start(struct snd_us
ep->active_mask = 0;
ep->unlink_mask = 0;
ep->phase = 0;
- ep->sample_accum = 0;

snd_usb_endpoint_start_quirk(ep);

--- a/sound/usb/endpoint.h
+++ b/sound/usb/endpoint.h
@@ -28,7 +28,6 @@ void snd_usb_endpoint_release(struct snd
void snd_usb_endpoint_free(struct snd_usb_endpoint *ep);

int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep);
-int snd_usb_endpoint_slave_next_packet_size(struct snd_usb_endpoint *ep);
int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep);

void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -1558,8 +1558,6 @@ static void prepare_playback_urb(struct
for (i = 0; i < ctx->packets; i++) {
if (ctx->packet_size[i])
counts = ctx->packet_size[i];
- else if (ep->sync_master)
- counts = snd_usb_endpoint_slave_next_packet_size(ep);
else
counts = snd_usb_endpoint_next_packet_size(ep);