linux/sound/usb/usbaudio.h
Takashi Iwai f4df2c5f97 ALSA: usb-audio: Fix inconsistent card PM state after resume
commit 862b2509d157c629dd26d7ac6c6cdbf043d332eb upstream.

When a USB-audio interface gets runtime-suspended via auto-pm feature,
the driver suspends all functionality and increment
chip->num_suspended_intf.  Later on, when the system gets suspended to
S3, the driver increments chip->num_suspended_intf again, skips the
device changes, and sets the card power state to
SNDRV_CTL_POWER_D3hot.  In return, when the system gets resumed from
S3, the resume callback decrements chip->num_suspended_intf.  Since
this refcount is still not zero (it's been runtime-suspended), the
whole resume is skipped.  But there is a small pitfall here.

The problem is that the driver doesn't restore the card power state
after this resume call, leaving it as SNDRV_CTL_POWER_D3hot.  So,
even after the system resume finishes, the card instance still appears
as if it were system-suspended, and this confuses many ioctl accesses
that are blocked unexpectedly.

In details, we have two issues behind the scene: one is that the card
power state is changed only when the refcount becomes zero, and
another is that the prior auto-suspend check is kept in a boolean
flag.  Although the latter problem is almost negligible since the
auto-pm feature is imposed only on the primary interface, but this can
be a potential problem on the devices with multiple interfaces.

This patch addresses those issues by the following:

- Replace chip->autosuspended boolean flag with chip->system_suspend
  counter

- At the first system-suspend, chip->num_suspended_intf is recorded to
  chip->system_suspend

- At system-resume, the card power state is restored when the
  chip->num_suspended_intf refcount reaches to chip->system_suspend,
  i.e. the state returns to the auto-suspended

Also, the patch fixes yet another hidden problem by the code
refactoring along with the fixes above: namely, when some resume
procedure failed, the driver left chip->num_suspended_intf that was
already decreased, and it might lead to the refcount unbalance.
In the new code, the refcount decrement is done after the whole resume
procedure, and the problem is avoided as well.

Fixes: 0662292aec05 ("ALSA: usb-audio: Handle normal and auto-suspend equally")
Reported-and-tested-by: Macpaul Lin <macpaul.lin@mediatek.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200603153709.6293-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-20 10:24:09 +02:00

125 lines
3.5 KiB
C

#ifndef __USBAUDIO_H
#define __USBAUDIO_H
/*
* (Tentative) USB Audio Driver for ALSA
*
* Copyright (c) 2002 by Takashi Iwai <tiwai@suse.de>
*
*
* 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
*/
/* handling of USB vendor/product ID pairs as 32-bit numbers */
#define USB_ID(vendor, product) (((vendor) << 16) | (product))
#define USB_ID_VENDOR(id) ((id) >> 16)
#define USB_ID_PRODUCT(id) ((u16)(id))
/*
*
*/
struct snd_usb_audio {
int index;
struct usb_device *dev;
struct snd_card *card;
struct usb_interface *pm_intf;
u32 usb_id;
struct mutex mutex;
unsigned int system_suspend;
atomic_t active;
atomic_t shutdown;
atomic_t usage_count;
wait_queue_head_t shutdown_wait;
unsigned int txfr_quirk:1; /* Subframe boundaries on transfers */
unsigned int tx_length_quirk:1; /* Put length specifier in transfers */
int num_interfaces;
int num_suspended_intf;
int sample_rate_read_error;
struct list_head pcm_list; /* list of pcm streams */
struct list_head ep_list; /* list of audio-related endpoints */
int pcm_devs;
struct list_head midi_list; /* list of midi interfaces */
struct list_head mixer_list; /* list of mixer interfaces */
int setup; /* from the 'device_setup' module param */
bool autoclock; /* from the 'autoclock' module param */
struct usb_host_interface *ctrl_intf; /* the audio control interface */
};
#define usb_audio_err(chip, fmt, args...) \
dev_err(&(chip)->dev->dev, fmt, ##args)
#define usb_audio_warn(chip, fmt, args...) \
dev_warn(&(chip)->dev->dev, fmt, ##args)
#define usb_audio_info(chip, fmt, args...) \
dev_info(&(chip)->dev->dev, fmt, ##args)
#define usb_audio_dbg(chip, fmt, args...) \
dev_dbg(&(chip)->dev->dev, fmt, ##args)
/*
* Information about devices with broken descriptors
*/
/* special values for .ifnum */
#define QUIRK_NO_INTERFACE -2
#define QUIRK_ANY_INTERFACE -1
enum quirk_type {
QUIRK_IGNORE_INTERFACE,
QUIRK_COMPOSITE,
QUIRK_AUTODETECT,
QUIRK_MIDI_STANDARD_INTERFACE,
QUIRK_MIDI_FIXED_ENDPOINT,
QUIRK_MIDI_YAMAHA,
QUIRK_MIDI_ROLAND,
QUIRK_MIDI_MIDIMAN,
QUIRK_MIDI_NOVATION,
QUIRK_MIDI_RAW_BYTES,
QUIRK_MIDI_EMAGIC,
QUIRK_MIDI_CME,
QUIRK_MIDI_AKAI,
QUIRK_MIDI_US122L,
QUIRK_MIDI_FTDI,
QUIRK_MIDI_CH345,
QUIRK_AUDIO_STANDARD_INTERFACE,
QUIRK_AUDIO_FIXED_ENDPOINT,
QUIRK_AUDIO_EDIROL_UAXX,
QUIRK_AUDIO_ALIGN_TRANSFER,
QUIRK_AUDIO_STANDARD_MIXER,
QUIRK_TYPE_COUNT
};
struct snd_usb_audio_quirk {
const char *vendor_name;
const char *product_name;
int16_t ifnum;
uint16_t type;
const void *data;
};
#define combine_word(s) ((*(s)) | ((unsigned int)(s)[1] << 8))
#define combine_triple(s) (combine_word(s) | ((unsigned int)(s)[2] << 16))
#define combine_quad(s) (combine_triple(s) | ((unsigned int)(s)[3] << 24))
int snd_usb_lock_shutdown(struct snd_usb_audio *chip);
void snd_usb_unlock_shutdown(struct snd_usb_audio *chip);
#endif /* __USBAUDIO_H */