linux/sound/usb/clock.c
Takashi Iwai 57dd5414a0 ALSA: usb-audio: Limit retrying sample rate reads
There are many USB audio devices with buggy firmware that don't react
with the sample rate reading properly.  This often results in the
flood of error messages and slowing down the operation.

The sample rate read back is basically only for confirming the sample
rate setup, and it's not critically important.  As a compromise, in
this patch, we stop the sample rate read back once when the device
gives errors more than tolerance (twice, as of now).  This should
improve most of error cases while we still can catch the firmware
bugginess.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2016-04-29 11:49:04 +02:00

434 lines
12 KiB
C

/*
* Clock domain and sample rate management functions
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include <linux/bitops.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/usb.h>
#include <linux/usb/audio.h>
#include <linux/usb/audio-v2.h>
#include <sound/core.h>
#include <sound/info.h>
#include <sound/pcm.h>
#include "usbaudio.h"
#include "card.h"
#include "helper.h"
#include "clock.h"
#include "quirks.h"
static struct uac_clock_source_descriptor *
snd_usb_find_clock_source(struct usb_host_interface *ctrl_iface,
int clock_id)
{
struct uac_clock_source_descriptor *cs = NULL;
while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
ctrl_iface->extralen,
cs, UAC2_CLOCK_SOURCE))) {
if (cs->bClockID == clock_id)
return cs;
}
return NULL;
}
static struct uac_clock_selector_descriptor *
snd_usb_find_clock_selector(struct usb_host_interface *ctrl_iface,
int clock_id)
{
struct uac_clock_selector_descriptor *cs = NULL;
while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
ctrl_iface->extralen,
cs, UAC2_CLOCK_SELECTOR))) {
if (cs->bClockID == clock_id)
return cs;
}
return NULL;
}
static struct uac_clock_multiplier_descriptor *
snd_usb_find_clock_multiplier(struct usb_host_interface *ctrl_iface,
int clock_id)
{
struct uac_clock_multiplier_descriptor *cs = NULL;
while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
ctrl_iface->extralen,
cs, UAC2_CLOCK_MULTIPLIER))) {
if (cs->bClockID == clock_id)
return cs;
}
return NULL;
}
static int uac_clock_selector_get_val(struct snd_usb_audio *chip, int selector_id)
{
unsigned char buf;
int ret;
ret = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0),
UAC2_CS_CUR,
USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
UAC2_CX_CLOCK_SELECTOR << 8,
snd_usb_ctrl_intf(chip) | (selector_id << 8),
&buf, sizeof(buf));
if (ret < 0)
return ret;
return buf;
}
static int uac_clock_selector_set_val(struct snd_usb_audio *chip, int selector_id,
unsigned char pin)
{
int ret;
ret = snd_usb_ctl_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0),
UAC2_CS_CUR,
USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
UAC2_CX_CLOCK_SELECTOR << 8,
snd_usb_ctrl_intf(chip) | (selector_id << 8),
&pin, sizeof(pin));
if (ret < 0)
return ret;
if (ret != sizeof(pin)) {
usb_audio_err(chip,
"setting selector (id %d) unexpected length %d\n",
selector_id, ret);
return -EINVAL;
}
ret = uac_clock_selector_get_val(chip, selector_id);
if (ret < 0)
return ret;
if (ret != pin) {
usb_audio_err(chip,
"setting selector (id %d) to %x failed (current: %d)\n",
selector_id, pin, ret);
return -EINVAL;
}
return ret;
}
static bool uac_clock_source_is_valid(struct snd_usb_audio *chip, int source_id)
{
int err;
unsigned char data;
struct usb_device *dev = chip->dev;
struct uac_clock_source_descriptor *cs_desc =
snd_usb_find_clock_source(chip->ctrl_intf, source_id);
if (!cs_desc)
return 0;
/* If a clock source can't tell us whether it's valid, we assume it is */
if (!uac2_control_is_readable(cs_desc->bmControls,
UAC2_CS_CONTROL_CLOCK_VALID - 1))
return 1;
err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
UAC2_CS_CONTROL_CLOCK_VALID << 8,
snd_usb_ctrl_intf(chip) | (source_id << 8),
&data, sizeof(data));
if (err < 0) {
dev_warn(&dev->dev,
"%s(): cannot get clock validity for id %d\n",
__func__, source_id);
return 0;
}
return !!data;
}
static int __uac_clock_find_source(struct snd_usb_audio *chip,
int entity_id, unsigned long *visited,
bool validate)
{
struct uac_clock_source_descriptor *source;
struct uac_clock_selector_descriptor *selector;
struct uac_clock_multiplier_descriptor *multiplier;
entity_id &= 0xff;
if (test_and_set_bit(entity_id, visited)) {
usb_audio_warn(chip,
"%s(): recursive clock topology detected, id %d.\n",
__func__, entity_id);
return -EINVAL;
}
/* first, see if the ID we're looking for is a clock source already */
source = snd_usb_find_clock_source(chip->ctrl_intf, entity_id);
if (source) {
entity_id = source->bClockID;
if (validate && !uac_clock_source_is_valid(chip, entity_id)) {
usb_audio_err(chip,
"clock source %d is not valid, cannot use\n",
entity_id);
return -ENXIO;
}
return entity_id;
}
selector = snd_usb_find_clock_selector(chip->ctrl_intf, entity_id);
if (selector) {
int ret, i, cur;
/* the entity ID we are looking for is a selector.
* find out what it currently selects */
ret = uac_clock_selector_get_val(chip, selector->bClockID);
if (ret < 0)
return ret;
/* Selector values are one-based */
if (ret > selector->bNrInPins || ret < 1) {
usb_audio_err(chip,
"%s(): selector reported illegal value, id %d, ret %d\n",
__func__, selector->bClockID, ret);
return -EINVAL;
}
cur = ret;
ret = __uac_clock_find_source(chip, selector->baCSourceID[ret - 1],
visited, validate);
if (!validate || ret > 0 || !chip->autoclock)
return ret;
/* The current clock source is invalid, try others. */
for (i = 1; i <= selector->bNrInPins; i++) {
int err;
if (i == cur)
continue;
ret = __uac_clock_find_source(chip, selector->baCSourceID[i - 1],
visited, true);
if (ret < 0)
continue;
err = uac_clock_selector_set_val(chip, entity_id, i);
if (err < 0)
continue;
usb_audio_info(chip,
"found and selected valid clock source %d\n",
ret);
return ret;
}
return -ENXIO;
}
/* FIXME: multipliers only act as pass-thru element for now */
multiplier = snd_usb_find_clock_multiplier(chip->ctrl_intf, entity_id);
if (multiplier)
return __uac_clock_find_source(chip, multiplier->bCSourceID,
visited, validate);
return -EINVAL;
}
/*
* For all kinds of sample rate settings and other device queries,
* the clock source (end-leaf) must be used. However, clock selectors,
* clock multipliers and sample rate converters may be specified as
* clock source input to terminal. This functions walks the clock path
* to its end and tries to find the source.
*
* The 'visited' bitfield is used internally to detect recursive loops.
*
* Returns the clock source UnitID (>=0) on success, or an error.
*/
int snd_usb_clock_find_source(struct snd_usb_audio *chip, int entity_id,
bool validate)
{
DECLARE_BITMAP(visited, 256);
memset(visited, 0, sizeof(visited));
return __uac_clock_find_source(chip, entity_id, visited, validate);
}
static int set_sample_rate_v1(struct snd_usb_audio *chip, int iface,
struct usb_host_interface *alts,
struct audioformat *fmt, int rate)
{
struct usb_device *dev = chip->dev;
unsigned int ep;
unsigned char data[3];
int err, crate;
if (get_iface_desc(alts)->bNumEndpoints < 1)
return -EINVAL;
ep = get_endpoint(alts, 0)->bEndpointAddress;
/* if endpoint doesn't have sampling rate control, bail out */
if (!(fmt->attributes & UAC_EP_CS_ATTR_SAMPLE_RATE))
return 0;
data[0] = rate;
data[1] = rate >> 8;
data[2] = rate >> 16;
if ((err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_OUT,
UAC_EP_CS_ATTR_SAMPLE_RATE << 8, ep,
data, sizeof(data))) < 0) {
dev_err(&dev->dev, "%d:%d: cannot set freq %d to ep %#x\n",
iface, fmt->altsetting, rate, ep);
return err;
}
/* Don't check the sample rate for devices which we know don't
* support reading */
if (snd_usb_get_sample_rate_quirk(chip))
return 0;
/* the firmware is likely buggy, don't repeat to fail too many times */
if (chip->sample_rate_read_error > 2)
return 0;
if ((err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC_GET_CUR,
USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_IN,
UAC_EP_CS_ATTR_SAMPLE_RATE << 8, ep,
data, sizeof(data))) < 0) {
dev_err(&dev->dev, "%d:%d: cannot get freq at ep %#x\n",
iface, fmt->altsetting, ep);
chip->sample_rate_read_error++;
return 0; /* some devices don't support reading */
}
crate = data[0] | (data[1] << 8) | (data[2] << 16);
if (crate != rate) {
dev_warn(&dev->dev, "current rate %d is different from the runtime rate %d\n", crate, rate);
// runtime->rate = crate;
}
return 0;
}
static int get_sample_rate_v2(struct snd_usb_audio *chip, int iface,
int altsetting, int clock)
{
struct usb_device *dev = chip->dev;
__le32 data;
int err;
err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
UAC2_CS_CONTROL_SAM_FREQ << 8,
snd_usb_ctrl_intf(chip) | (clock << 8),
&data, sizeof(data));
if (err < 0) {
dev_warn(&dev->dev, "%d:%d: cannot get freq (v2): err %d\n",
iface, altsetting, err);
return 0;
}
return le32_to_cpu(data);
}
static int set_sample_rate_v2(struct snd_usb_audio *chip, int iface,
struct usb_host_interface *alts,
struct audioformat *fmt, int rate)
{
struct usb_device *dev = chip->dev;
__le32 data;
int err, cur_rate, prev_rate;
int clock;
bool writeable;
struct uac_clock_source_descriptor *cs_desc;
clock = snd_usb_clock_find_source(chip, fmt->clock, true);
if (clock < 0)
return clock;
prev_rate = get_sample_rate_v2(chip, iface, fmt->altsetting, clock);
if (prev_rate == rate)
return 0;
cs_desc = snd_usb_find_clock_source(chip->ctrl_intf, clock);
writeable = uac2_control_is_writeable(cs_desc->bmControls, UAC2_CS_CONTROL_SAM_FREQ - 1);
if (writeable) {
data = cpu_to_le32(rate);
err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC2_CS_CUR,
USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
UAC2_CS_CONTROL_SAM_FREQ << 8,
snd_usb_ctrl_intf(chip) | (clock << 8),
&data, sizeof(data));
if (err < 0) {
usb_audio_err(chip,
"%d:%d: cannot set freq %d (v2): err %d\n",
iface, fmt->altsetting, rate, err);
return err;
}
cur_rate = get_sample_rate_v2(chip, iface, fmt->altsetting, clock);
} else {
cur_rate = prev_rate;
}
if (cur_rate != rate) {
if (!writeable) {
usb_audio_warn(chip,
"%d:%d: freq mismatch (RO clock): req %d, clock runs @%d\n",
iface, fmt->altsetting, rate, cur_rate);
return -ENXIO;
}
usb_audio_dbg(chip,
"current rate %d is different from the runtime rate %d\n",
cur_rate, rate);
}
/* Some devices doesn't respond to sample rate changes while the
* interface is active. */
if (rate != prev_rate) {
usb_set_interface(dev, iface, 0);
snd_usb_set_interface_quirk(dev);
usb_set_interface(dev, iface, fmt->altsetting);
snd_usb_set_interface_quirk(dev);
}
return 0;
}
int snd_usb_init_sample_rate(struct snd_usb_audio *chip, int iface,
struct usb_host_interface *alts,
struct audioformat *fmt, int rate)
{
switch (fmt->protocol) {
case UAC_VERSION_1:
default:
return set_sample_rate_v1(chip, iface, alts, fmt, rate);
case UAC_VERSION_2:
return set_sample_rate_v2(chip, iface, alts, fmt, rate);
}
}