ALSA: usb - Remove trailing spaces from USB card name strings

Some USB devices give trailing spaces in strings returned from
usb_string(). This confuses the automatic card-id creation, resulting
al

ALSA: usb - Remove trailing spaces from USB card name strings

Some USB devices give trailing spaces in strings returned from
usb_string(). This confuses the automatic card-id creation, resulting
always in "default".
This patch fixes the behavior by removing trailing spaces.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

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ALSA: usbaudio: implement USB autosuspend

Devices are autosuspended if no pcm nor midi channel is open
Mixer devices may be opened. This way they are active when
in use to play or record sound, but

ALSA: usbaudio: implement USB autosuspend

Devices are autosuspended if no pcm nor midi channel is open
Mixer devices may be opened. This way they are active when
in use to play or record sound, but can be suspended while
users have a mixer application running.

[Small clean-ups using static inline by tiwai]

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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ALSA: usbaudio: fix suspend/resume

- ESHUTDOWN must be correctly handled
- the optional interrupt endpoint's URB must be stopped and restarted

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-

ALSA: usbaudio: fix suspend/resume

- ESHUTDOWN must be correctly handled
- the optional interrupt endpoint's URB must be stopped and restarted

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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ALSA: usb-audio: fix oops due to cleanup race when disconnecting

When a USB audio device is disconnected, snd_usb_audio_disconnect()
kills all audio URBs. At the same time, the application, after b

ALSA: usb-audio: fix oops due to cleanup race when disconnecting

When a USB audio device is disconnected, snd_usb_audio_disconnect()
kills all audio URBs. At the same time, the application, after being
notified of the disconnection, might close the device, in which case
ALSA calls the .hw_free callback, which should free the URBs too.

Commit de1b8b93a0ba "[ALSA] Fix hang-up at disconnection of usb-audio"
prevented snd_usb_hw_free() from freeing the URBs to avoid a hang that
resulted from this race, but this introduced another race because the
URB callbacks could now be executed after snd_usb_hw_free() has
returned, and try to access already freed data.

Fix the first race by introducing a mutex to serialize the disconnect
callback and all PCM callbacks that manage URBs (hw_free and hw_params).

Reported-and-tested-by: Pierre-Louis Bossart <pierre-louis.bossart@intel.com>
Cc: <stable@kernel.org>
[CL: also serialize hw_params callback]
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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ALSA: usb - Release capture substream URBs properly

Due to the wrong "return" in the loop, a capture substream won't be
released at disconnection properly if the device is capture only and has
no pl

ALSA: usb - Release capture substream URBs properly

Due to the wrong "return" in the loop, a capture substream won't be
released at disconnection properly if the device is capture only and has
no playback substream. This caused Oops occasionally at the device
reconnection.

Reported-by: Kim Minhyoung <minhyoung.kim@lge.com>
Cc: <stable@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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ALSA: usb-audio: fix detection of vendor-specific device protocol settings

The Audio Class v2 support code in 2.6.35 added checks for the
bInterfaceProtocol field. However, there are devices (usual

ALSA: usb-audio: fix detection of vendor-specific device protocol settings

The Audio Class v2 support code in 2.6.35 added checks for the
bInterfaceProtocol field. However, there are devices (usually those
detected by vendor-specific quirks) that do not have one of the
predefined values in this field, which made the driver reject them.

To fix this regression, restore the old behaviour, i.e., assume that
a device with an unknown bInterfaceProtocol field (other than
UAC_VERSION_2) has more or less UAC-v1-compatible descriptors.

[compile warning fixes by tiwai]

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Cc: Daniel Mack <daniel@caiaq.de>
Cc: <stable@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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ALSA: usb-audio: Assume first control interface is for audio

For devices with more than one control interface, let's assume the first
one contains the audio controls. Unfortunately, there is no fiel

ALSA: usb-audio: Assume first control interface is for audio

For devices with more than one control interface, let's assume the first
one contains the audio controls. Unfortunately, there is no field in any
of the descriptors to tell us whether a control interface is for audio
or MIDI controls, so a better check is not easy to implement.

On a composite device with audio and MIDI functions, for example, the
code currently overwrites chip->ctrl_intf, causing operations on the
control interface to fail if they are issued after the device probe.

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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ALSA: usb: USB3 SuperSpeed sound support

This is V2 of the patch, after feedback from Clemens and Daniel.

This patch adds SuperSpeed support to the USB drivers under sound/. It adds
tests for USB_S

ALSA: usb: USB3 SuperSpeed sound support

This is V2 of the patch, after feedback from Clemens and Daniel.

This patch adds SuperSpeed support to the USB drivers under sound/. It adds
tests for USB_SPEED_SUPER to the appropriate places that check for the USB
speed.

This patch has been tested with our SS USB3 device emulating a set of Yamaha
speakers and a Logitech microphone, but with the descriptors modified to add
USB3 support. It has also been tested with the real speakers and microphone,
to make sure that USB2 devices still work.

Signed-off-by: Paul Zimmerman <paulz@synopsys.com>
Cc: Clemens Ladisch <clemens@ladisch.de>
Cc: Daniel Mack <daniel@caiaq.de>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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ALSA: usb-audio: unify UAC macros and struct names

Get rid of the last occurances of _v1 suffixes, and move the version
number right after the "uac" string. Now things are consitent again.

Sorry fo

ALSA: usb-audio: unify UAC macros and struct names

Get rid of the last occurances of _v1 suffixes, and move the version
number right after the "uac" string. Now things are consitent again.

Sorry for the forth and back, but it just looks much nicer this way.

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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ALSA: usb-audio: parse clock topology of UAC2 devices

Audio devices which comply to the UAC2 standard can export complex clock
topologies in its descriptors and set up links between them.

The entit

ALSA: usb-audio: parse clock topology of UAC2 devices

Audio devices which comply to the UAC2 standard can export complex clock
topologies in its descriptors and set up links between them.

The entities that are defined are

- clock sources, which define the end-leafs.
- clock selectors, which act as switch to select one out of many
possible clocks sources.
- clock multipliers, which have an input clock source, and act as clock
source again. They can be used to derive one clock from another.

All sample rate changes, clock validity queries and the like must go to
clock source elements, while clock selectors and multipliers can be used
as terminal clock source.

The following patch adds a parser for these elements and functions to
iterate over the tree and find the leaf nodes (clock sources).

The samplerate set functions were moved to the new clock.c file.

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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ALSA: usb: fix usb build error when PM is not enabled

Fix build errors when CONFIG_PM is not enabled:

sound/usb/card.c:629: error: 'usb_audio_suspend' undeclared here (not in a function)
sound/usb/

ALSA: usb: fix usb build error when PM is not enabled

Fix build errors when CONFIG_PM is not enabled:

sound/usb/card.c:629: error: 'usb_audio_suspend' undeclared here (not in a function)
sound/usb/card.c:630: error: 'usb_audio_resume' undeclared here (not in a function)

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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ALSA: usbmixer: rename usbmixer.[ch] -> mixer.[ch]

For clearer namespace, also rename usbmixer_maps.c -> mixer_maps.c

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Cc: Clemens Ladisch <clemens@ladis

ALSA: usbmixer: rename usbmixer.[ch] -> mixer.[ch]

For clearer namespace, also rename usbmixer_maps.c -> mixer_maps.c

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Cc: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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linux/usb/audio.h: split header

- Split the audio.h file in two to clearly denote the differences
between the standards.
- Add many more defines to audio-v2.h. Most of them are not currently
use

linux/usb/audio.h: split header

- Split the audio.h file in two to clearly denote the differences
between the standards.
- Add many more defines to audio-v2.h. Most of them are not currently
used.
- Replaced a magic value with a proper define

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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ALSA: usb-audio: refactor code

Clean up the usb audio driver by factoring out a lot of functions to
separate files. Code for procfs, quirks, urbs, format parsers etc all
got a new home now.

Moved a

ALSA: usb-audio: refactor code

Clean up the usb audio driver by factoring out a lot of functions to
separate files. Code for procfs, quirks, urbs, format parsers etc all
got a new home now.

Moved almost all special quirk handling to quirks.c and introduced new
generic functions to handle them, so the exceptions do not pollute the
whole driver.

Renamed usbaudio.c to card.c because this is what it actually does now.
Renamed usbmidi.c to midi.c for namespace clarity.
Removed more things from usbaudio.h.

The non-standard drivers were adopted accordingly.

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Cc: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

show more ...

ALSA: usb-audio: Fix superfluous autosuspend recovery

commit 66291b6adb66dd3bc96b0f594d88c2ff1300d95f upstream.

The change to restore the autosuspend from the disabled state uses a

ALSA: usb-audio: Fix superfluous autosuspend recovery

commit 66291b6adb66dd3bc96b0f594d88c2ff1300d95f upstream.

The change to restore the autosuspend from the disabled state uses a
wrong check: namely, it should have been the exact comparison of the
quirk_type instead of the bitwise and (&). Otherwise it matches
wrongly with the other quirk types.

Although re-enabling the autosuspend for the already enabled device
shouldn't matter much, it's better to fix the unbalanced call.

Fixes: 9799110825db ("ALSA: usb-audio: Disable USB autosuspend properly in setup_disable_autosuspend()")
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/s5hr1flh9ov.wl-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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ALSA: usb-audio: Add error checks for usb_driver_claim_interface() calls

[ Upstream commit 5fb45414ae03421255593fd5556aa2d1d82303aa ]

There are a few calls of usb_driver_claim_inter

ALSA: usb-audio: Add error checks for usb_driver_claim_interface() calls

[ Upstream commit 5fb45414ae03421255593fd5556aa2d1d82303aa ]

There are a few calls of usb_driver_claim_interface() but all of those
miss the proper error checks, as reported by Coverity. This patch
adds those missing checks.

Along with it, replace the magic pointer with -1 with a constant
USB_AUDIO_IFACE_UNUSED for better readability.

Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
Addresses-Coverity-ID: 1475943 ("Error handling issues")
Addresses-Coverity-ID: 1475944 ("Error handling issues")
Addresses-Coverity-ID: 1475945 ("Error handling issues")
Fixes: b1ce7ba619d9 ("ALSA: usb-audio: claim autodetected PCM interfaces all at once")
Fixes: e5779998bf8b ("ALSA: usb-audio: refactor code")
Link: https://lore.kernel.org/r/202104051059.FB7F3016@keescook
Link: https://lore.kernel.org/r/20210406113534.30455-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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ALSA: usb-audio: fix use after free in usb_audio_disconnect

commit c5aa956eaeb05fe87e33433d7fd9f5e4d23c7416 upstream.

The problem was in wrong "if" placement. chip->quirk_type is fr

ALSA: usb-audio: fix use after free in usb_audio_disconnect

commit c5aa956eaeb05fe87e33433d7fd9f5e4d23c7416 upstream.

The problem was in wrong "if" placement. chip->quirk_type is freed
in snd_card_free_when_closed(), but inside if statement it's accesed.

Fixes: 9799110825db ("ALSA: usb-audio: Disable USB autosuspend properly in setup_disable_autosuspend()")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/16da19126ff461e5e64a9aec648cce28fb8ed73e.1615242183.git.paskripkin@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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ALSA: usb-audio: fix NULL ptr dereference in usb_audio_probe

commit 30dea07180de3aa0ad613af88431ef4e34b5ef68 upstream.

syzbot reported null pointer dereference in usb_audio_probe.

ALSA: usb-audio: fix NULL ptr dereference in usb_audio_probe

commit 30dea07180de3aa0ad613af88431ef4e34b5ef68 upstream.

syzbot reported null pointer dereference in usb_audio_probe.
The problem was in case, when quirk == NULL. It's not an
error condition, so quirk must be checked before dereferencing.

Call Trace:
usb_probe_interface+0x315/0x7f0 drivers/usb/core/driver.c:396
really_probe+0x291/0xe60 drivers/base/dd.c:554
driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:740
__device_attach_driver+0x1d1/0x290 drivers/base/dd.c:846
bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431
__device_attach+0x228/0x4a0 drivers/base/dd.c:914
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491
device_add+0xbdb/0x1db0 drivers/base/core.c:3242
usb_set_configuration+0x113f/0x1910 drivers/usb/core/message.c:2164
usb_generic_driver_probe+0xba/0x100 drivers/usb/core/generic.c:238
usb_probe_device+0xd9/0x2c0 drivers/usb/core/driver.c:293
really_probe+0x291/0xe60 drivers/base/dd.c:554
driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:740
__device_attach_driver+0x1d1/0x290 drivers/base/dd.c:846
bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431
__device_attach+0x228/0x4a0 drivers/base/dd.c:914
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491
device_add+0xbdb/0x1db0 drivers/base/core.c:3242
usb_new_device.cold+0x721/0x1058 drivers/usb/core/hub.c:2555
hub_port_connect drivers/usb/core/hub.c:5223 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5363 [inline]
port_event drivers/usb/core/hub.c:5509 [inline]
hub_event+0x2357/0x4320 drivers/usb/core/hub.c:5591
process_one_work+0x98d/0x1600 kernel/workqueue.c:2275
worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
kthread+0x3b1/0x4a0 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Reported-by: syzbot+719da9b149a931f5143f@syzkaller.appspotmail.com
Fixes: 9799110825db ("ALSA: usb-audio: Disable USB autosuspend properly in setup_disable_autosuspend()")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/f1ebad6e721412843bd1b12584444c0a63c6b2fb.1615242183.git.paskripkin@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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ALSA: usb-audio: Disable USB autosuspend properly in setup_disable_autosuspend()

commit 9799110825dba087c2bdce886977cf84dada2005 upstream.

Rear audio on Lenovo ThinkStation P620 sto

ALSA: usb-audio: Disable USB autosuspend properly in setup_disable_autosuspend()

commit 9799110825dba087c2bdce886977cf84dada2005 upstream.

Rear audio on Lenovo ThinkStation P620 stops working after commit
1965c4364bdd ("ALSA: usb-audio: Disable autosuspend for Lenovo
ThinkStation P620"):
[ 6.013526] usbcore: registered new interface driver snd-usb-audio
[ 6.023064] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x100, wIndex = 0x0, type = 1
[ 6.023083] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x202, wIndex = 0x0, type = 4
[ 6.023090] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x100, wIndex = 0x0, type = 1
[ 6.023098] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x202, wIndex = 0x0, type = 4
[ 6.023103] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x100, wIndex = 0x0, type = 1
[ 6.023110] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x202, wIndex = 0x0, type = 4
[ 6.045846] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x100, wIndex = 0x0, type = 1
[ 6.045866] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x202, wIndex = 0x0, type = 4
[ 6.045877] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x100, wIndex = 0x0, type = 1
[ 6.045886] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x202, wIndex = 0x0, type = 4
[ 6.045894] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x100, wIndex = 0x0, type = 1
[ 6.045908] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x202, wIndex = 0x0, type = 4

I overlooked the issue because when I was working on the said commit,
only the front audio is tested. Apology for that.

Changing supports_autosuspend in driver is too late for disabling
autosuspend, because it was already used by USB probe routine, so it can
break the balance on the following code that depends on
supports_autosuspend.

Fix it by using usb_disable_autosuspend() helper, and balance the
suspend count in disconnect callback.

Fixes: 1965c4364bdd ("ALSA: usb-audio: Disable autosuspend for Lenovo ThinkStation P620")
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210304043419.287191-1-kai.heng.feng@canonical.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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ALSA: usb-audio: Add alias entry for ASUS PRIME TRX40 PRO-S

commit 525d9c57d0eeeb660d9b25e5b2d1c95975e3ba95 upstream.

ASUS PRIME TRX40 PRO-S mobo with 0b05:1918 needs the same quirk

ALSA: usb-audio: Add alias entry for ASUS PRIME TRX40 PRO-S

commit 525d9c57d0eeeb660d9b25e5b2d1c95975e3ba95 upstream.

ASUS PRIME TRX40 PRO-S mobo with 0b05:1918 needs the same quirk alias
for another ASUS mobo (0b05:1917) for the proper mixer mapping, etc.
Add the corresponding entry.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=210783
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20201221080159.24468-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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ALSA: usb-audio: Use ALC1220-VB-DT mapping for ASUS ROG Strix TRX40 mobo

ASUS ROG Strix also uses ALC1220-VB-DT, so adjust the mapping and add
profile name to let userspace pick correct

ALSA: usb-audio: Use ALC1220-VB-DT mapping for ASUS ROG Strix TRX40 mobo

ASUS ROG Strix also uses ALC1220-VB-DT, so adjust the mapping and add
profile name to let userspace pick correct UCM profile.

BugLink: https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/issues/1031
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Link: https://lore.kernel.org/r/20201115153843.1109200-1-kai.heng.feng@canonical.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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ALSA: usb-audio: Move device rename and profile quirks to an internal table

So far we've added the devices that need vendor/product string renames
or the profile setup into the standard

ALSA: usb-audio: Move device rename and profile quirks to an internal table

So far we've added the devices that need vendor/product string renames
or the profile setup into the standard quirk table in quirks-table.h.
This table is imported into the primary USB audio device entry, hence
it's all exported for the probing so that udev and co can take a look
at it. OTOH, for renaming or profile setup, we don't need to expose
those explicit entries because the probe itself follows the standard
way. That said, we're exposing unnecessarily too many entries.

This patch moves such internal quirk entries into the own table, and
reduces the exported device table size. Along with the moving items,
re-arrange the entries in the proper order.

Link: https://lore.kernel.org/r/20200817082140.20232-2-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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ALSA: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall

ALSA: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20200708203236.GA5112@embeddedor
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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ALSA: usb-audio: Manage auto-pm of all bundled interfaces

Currently USB-audio driver manages the auto-pm of the primary
interface although a card may consist of multiple interfaces.

ALSA: usb-audio: Manage auto-pm of all bundled interfaces

Currently USB-audio driver manages the auto-pm of the primary
interface although a card may consist of multiple interfaces.
This may leave the secondary and other interfaces left running
unnecessarily after the auto-suspend.

This patch allows the driver managing the auto-pm of all bundled
interfaces per card. The chip->pm_intf field is extended as
chip->intf[] to contain the array of assigned interfaces, and the
runtime-PM is performed to all those interfaces.

Tested-by: Macpaul Lin <macpaul.lin@mediatek.com>
Link: https://lore.kernel.org/r/20200605064117.28504-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

show more ...

ALSA: usb-audio: Fix inconsistent card PM state after resume

When a USB-audio interface gets runtime-suspended via auto-pm feature,
the driver suspends all functionality and increment

ALSA: usb-audio: Fix inconsistent card PM state after resume

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>

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