alistair23-linux/sound/usb/proc.c
Takashi Iwai 978520b75f ALSA: usb-audio: Fix races at disconnection
Close some races at disconnection of a USB audio device by adding the
chip->shutdown_mutex and chip->shutdown check at appropriate places.

The spots to put bandaids are:
- PCM prepare, hw_params and hw_free
- where the usb device is accessed for communication or get speed, in
 mixer.c and others; the device speed is now cached in subs->speed
 instead of accessing to chip->dev

The accesses in PCM open and close don't need the mutex protection
because these are already handled in the core PCM disconnection code.

The autosuspend/autoresume codes are still uncovered by this patch
because of possible mutex deadlocks.  They'll be covered by the
upcoming change to rwsem.

Also the mixer codes are untouched, too.  These will be fixed in
another patch, too.

Reported-by: Matthieu CASTET <matthieu.castet@parrot.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2012-10-30 11:06:54 +01:00

180 lines
6 KiB
C

/*
* 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/init.h>
#include <linux/usb.h>
#include <sound/core.h>
#include <sound/info.h>
#include <sound/pcm.h>
#include "usbaudio.h"
#include "helper.h"
#include "card.h"
#include "endpoint.h"
#include "proc.h"
/* convert our full speed USB rate into sampling rate in Hz */
static inline unsigned get_full_speed_hz(unsigned int usb_rate)
{
return (usb_rate * 125 + (1 << 12)) >> 13;
}
/* convert our high speed USB rate into sampling rate in Hz */
static inline unsigned get_high_speed_hz(unsigned int usb_rate)
{
return (usb_rate * 125 + (1 << 9)) >> 10;
}
/*
* common proc files to show the usb device info
*/
static void proc_audio_usbbus_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
{
struct snd_usb_audio *chip = entry->private_data;
if (!chip->shutdown)
snd_iprintf(buffer, "%03d/%03d\n", chip->dev->bus->busnum, chip->dev->devnum);
}
static void proc_audio_usbid_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
{
struct snd_usb_audio *chip = entry->private_data;
if (!chip->shutdown)
snd_iprintf(buffer, "%04x:%04x\n",
USB_ID_VENDOR(chip->usb_id),
USB_ID_PRODUCT(chip->usb_id));
}
void snd_usb_audio_create_proc(struct snd_usb_audio *chip)
{
struct snd_info_entry *entry;
if (!snd_card_proc_new(chip->card, "usbbus", &entry))
snd_info_set_text_ops(entry, chip, proc_audio_usbbus_read);
if (!snd_card_proc_new(chip->card, "usbid", &entry))
snd_info_set_text_ops(entry, chip, proc_audio_usbid_read);
}
/*
* proc interface for list the supported pcm formats
*/
static void proc_dump_substream_formats(struct snd_usb_substream *subs, struct snd_info_buffer *buffer)
{
struct list_head *p;
static char *sync_types[4] = {
"NONE", "ASYNC", "ADAPTIVE", "SYNC"
};
list_for_each(p, &subs->fmt_list) {
struct audioformat *fp;
snd_pcm_format_t fmt;
fp = list_entry(p, struct audioformat, list);
snd_iprintf(buffer, " Interface %d\n", fp->iface);
snd_iprintf(buffer, " Altset %d\n", fp->altsetting);
snd_iprintf(buffer, " Format:");
for (fmt = 0; fmt <= SNDRV_PCM_FORMAT_LAST; ++fmt)
if (fp->formats & (1uLL << fmt))
snd_iprintf(buffer, " %s",
snd_pcm_format_name(fmt));
snd_iprintf(buffer, "\n");
snd_iprintf(buffer, " Channels: %d\n", fp->channels);
snd_iprintf(buffer, " Endpoint: %d %s (%s)\n",
fp->endpoint & USB_ENDPOINT_NUMBER_MASK,
fp->endpoint & USB_DIR_IN ? "IN" : "OUT",
sync_types[(fp->ep_attr & USB_ENDPOINT_SYNCTYPE) >> 2]);
if (fp->rates & SNDRV_PCM_RATE_CONTINUOUS) {
snd_iprintf(buffer, " Rates: %d - %d (continuous)\n",
fp->rate_min, fp->rate_max);
} else {
unsigned int i;
snd_iprintf(buffer, " Rates: ");
for (i = 0; i < fp->nr_rates; i++) {
if (i > 0)
snd_iprintf(buffer, ", ");
snd_iprintf(buffer, "%d", fp->rate_table[i]);
}
snd_iprintf(buffer, "\n");
}
if (subs->speed != USB_SPEED_FULL)
snd_iprintf(buffer, " Data packet interval: %d us\n",
125 * (1 << fp->datainterval));
// snd_iprintf(buffer, " Max Packet Size = %d\n", fp->maxpacksize);
// snd_iprintf(buffer, " EP Attribute = %#x\n", fp->attributes);
}
}
static void proc_dump_ep_status(struct snd_usb_substream *subs,
struct snd_usb_endpoint *ep,
struct snd_info_buffer *buffer)
{
if (!ep)
return;
snd_iprintf(buffer, " Packet Size = %d\n", ep->curpacksize);
snd_iprintf(buffer, " Momentary freq = %u Hz (%#x.%04x)\n",
subs->speed == USB_SPEED_FULL
? get_full_speed_hz(ep->freqm)
: get_high_speed_hz(ep->freqm),
ep->freqm >> 16, ep->freqm & 0xffff);
if (ep->freqshift != INT_MIN) {
int res = 16 - ep->freqshift;
snd_iprintf(buffer, " Feedback Format = %d.%d\n",
(ep->syncmaxsize > 3 ? 32 : 24) - res, res);
}
}
static void proc_dump_substream_status(struct snd_usb_substream *subs, struct snd_info_buffer *buffer)
{
if (subs->running) {
snd_iprintf(buffer, " Status: Running\n");
snd_iprintf(buffer, " Interface = %d\n", subs->interface);
snd_iprintf(buffer, " Altset = %d\n", subs->altset_idx);
proc_dump_ep_status(subs, subs->data_endpoint, buffer);
proc_dump_ep_status(subs, subs->sync_endpoint, buffer);
} else {
snd_iprintf(buffer, " Status: Stop\n");
}
}
static void proc_pcm_format_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
{
struct snd_usb_stream *stream = entry->private_data;
snd_iprintf(buffer, "%s : %s\n", stream->chip->card->longname, stream->pcm->name);
if (stream->substream[SNDRV_PCM_STREAM_PLAYBACK].num_formats) {
snd_iprintf(buffer, "\nPlayback:\n");
proc_dump_substream_status(&stream->substream[SNDRV_PCM_STREAM_PLAYBACK], buffer);
proc_dump_substream_formats(&stream->substream[SNDRV_PCM_STREAM_PLAYBACK], buffer);
}
if (stream->substream[SNDRV_PCM_STREAM_CAPTURE].num_formats) {
snd_iprintf(buffer, "\nCapture:\n");
proc_dump_substream_status(&stream->substream[SNDRV_PCM_STREAM_CAPTURE], buffer);
proc_dump_substream_formats(&stream->substream[SNDRV_PCM_STREAM_CAPTURE], buffer);
}
}
void snd_usb_proc_pcm_format_add(struct snd_usb_stream *stream)
{
struct snd_info_entry *entry;
char name[32];
struct snd_card *card = stream->chip->card;
sprintf(name, "stream%d", stream->pcm_index);
if (!snd_card_proc_new(card, name, &entry))
snd_info_set_text_ops(entry, stream, proc_pcm_format_read);
}