[PATCH 5.19 609/717] ALSA: usb-audio: Register card at the last interface

Greg Kroah-Hartman
2022-10-22T08:42:45Z

From: Takashi Iwai <tiwai@suse.de>

[ Upstream commit 6392dcd1d0c7034ccf630ec55fc9e5810ecadf3b ]

The USB-audio driver matches per interface, and as default, it
registers the card instance at the very first instance. This can be a
problem for the devices that have multiple interfaces to be probed, as
the udev rule isn't applied properly for the later appearing
interfaces. Although we introduced the delayed_register option and
the quirks for covering those shortcomings, it's nothing but a
workaround for specific devices.

This patch is an another attempt to fix the problem in a more generic
way. Now the driver checks the whole USB device descriptor at the
very first time when an interface is attached to a sound card. It
looks at each matching interface in the descriptor and remembers the
last matching one. The snd_card_register() is invoked only when this
last interface is probed.

After this change, the quirks for the delayed registration become
superfluous, hence they are removed along with the patch. OTOH, the
delayed_register option is still kept, as it might be useful for some
corner cases (e.g. a special driver overtakes the interface probe from
the standard driver, and the last interface probe may miss).

Link: https://lore.kernel.org/r/20220904161247.16461-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
sound/usb/card.c | 32 +++++++++++++++++++++++++-------
sound/usb/quirks.c | 42 ------------------------------------------
sound/usb/quirks.h | 2 --
sound/usb/usbaudio.h | 1 +
4 files changed, 26 insertions(+), 51 deletions(-)

--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -690,7 +690,7 @@ static bool get_alias_id(struct usb_devi
return false;
}

-static bool check_delayed_register_option(struct snd_usb_audio *chip, int iface)
+static int check_delayed_register_option(struct snd_usb_audio *chip)
{
int i;
unsigned int id, inum;
@@ -699,14 +699,31 @@ static bool check_delayed_register_optio
if (delayed_register[i] &&
sscanf(delayed_register[i], "%x:%x", &id, &inum) == 2 &&
id == chip->usb_id)
- return iface < inum;
+ return inum;
}

- return false;
+ return -1;
}

static const struct usb_device_id usb_audio_ids[]; /* defined below */

+/* look for the last interface that matches with our ids and remember it */
+static void find_last_interface(struct snd_usb_audio *chip)
+{
+ struct usb_host_config *config = chip->dev->actconfig;
+ struct usb_interface *intf;
+ int i;
+
+ if (!config)
+ return;
+ for (i = 0; i < config->desc.bNumInterfaces; i++) {
+ intf = config->interface[i];
+ if (usb_match_id(intf, usb_audio_ids))
+ chip->last_iface = intf->altsetting[0].desc.bInterfaceNumber;
+ }
+ usb_audio_dbg(chip, "Found last interface = %d\n", chip->last_iface);
+}
+
/* look for the corresponding quirk */
static const struct snd_usb_audio_quirk *
get_alias_quirk(struct usb_device *dev, unsigned int id)
@@ -813,6 +830,7 @@ static int usb_audio_probe(struct usb_in
err = -ENODEV;
goto __error;
}
+ find_last_interface(chip);
}

if (chip->num_interfaces >= MAX_CARD_INTERFACES) {
@@ -862,11 +880,11 @@ static int usb_audio_probe(struct usb_in
chip->need_delayed_register = false; /* clear again */
}

- /* we are allowed to call snd_card_register() many times, but first
- * check to see if a device needs to skip it or do anything special
+ /* register card if we reach to the last interface or to the specified
+ * one given via option
*/
- if (!snd_usb_registration_quirk(chip, ifnum) &&
- !check_delayed_register_option(chip, ifnum)) {
+ if (check_delayed_register_option(chip) == ifnum ||
+ chip->last_iface == ifnum) {
err = snd_card_register(chip->card);
if (err < 0)
goto __error;
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -1729,48 +1729,6 @@ void snd_usb_audioformat_attributes_quir
}

/*
- * registration quirk:
- * the registration is skipped if a device matches with the given ID,
- * unless the interface reaches to the defined one. This is for delaying
- * the registration until the last known interface, so that the card and
- * devices appear at the same time.
- */
-
-struct registration_quirk {
- unsigned int usb_id; /* composed via USB_ID() */
- unsigned int interface; /* the interface to trigger register */
-};
-
-#define REG_QUIRK_ENTRY(vendor, product, iface) \
- { .usb_id = USB_ID(vendor, product), .interface = (iface) }
-
-static const struct registration_quirk registration_quirks[] = {
- REG_QUIRK_ENTRY(0x0951, 0x16d8, 2), /* Kingston HyperX AMP */
- REG_QUIRK_ENTRY(0x0951, 0x16ed, 2), /* Kingston HyperX Cloud Alpha S */
- REG_QUIRK_ENTRY(0x0951, 0x16ea, 2), /* Kingston HyperX Cloud Flight S */
- REG_QUIRK_ENTRY(0x0ecb, 0x1f46, 2), /* JBL Quantum 600 */
- REG_QUIRK_ENTRY(0x0ecb, 0x1f47, 2), /* JBL Quantum 800 */
- REG_QUIRK_ENTRY(0x0ecb, 0x1f4c, 2), /* JBL Quantum 400 */
- REG_QUIRK_ENTRY(0x0ecb, 0x2039, 2), /* JBL Quantum 400 */
- REG_QUIRK_ENTRY(0x0ecb, 0x203c, 2), /* JBL Quantum 600 */
- REG_QUIRK_ENTRY(0x0ecb, 0x203e, 2), /* JBL Quantum 800 */
- { 0 } /* terminator */
-};
-
-/* return true if skipping registration */
-bool snd_usb_registration_quirk(struct snd_usb_audio *chip, int iface)
-{
- const struct registration_quirk *q;
-
- for (q = registration_quirks; q->usb_id; q++)
- if (chip->usb_id == q->usb_id)
- return iface < q->interface;
-
- /* Register as normal */
- return false;
-}
-
-/*
* driver behavior quirk flags
*/
struct usb_audio_quirk_flags_table {
--- a/sound/usb/quirks.h
+++ b/sound/usb/quirks.h
@@ -48,8 +48,6 @@ void snd_usb_audioformat_attributes_quir
struct audioformat *fp,
int stream);

-bool snd_usb_registration_quirk(struct snd_usb_audio *chip, int iface);
-
void snd_usb_init_quirk_flags(struct snd_usb_audio *chip);

#endif /* __USBAUDIO_QUIRKS_H */
--- a/sound/usb/usbaudio.h
+++ b/sound/usb/usbaudio.h
@@ -37,6 +37,7 @@ struct snd_usb_audio {
unsigned int quirk_flags;
unsigned int need_delayed_register:1; /* warn for delayed registration */
int num_interfaces;
+ int last_iface;
int num_suspended_intf;
int sample_rate_read_error;