[PATCH v6 0/4] ALSA: usb-audio: improve module param quirk_flags

[PATCH v6 0/4] ALSA: usb-audio: improve module param quirk_flags

[Cryolitia PukNgae via B4 Relay]

As an implementation of what has been discussed previously[1].

1. https://lore.kernel.org/all/87h5xm5g7f.wl-tiwai@suse.de/

Signed-off-by: Cryolitia PukNgae <cryolitia@uniontech.com>
---
Changes in v6:
- Apply review commens, details corrected and wording revised
- Link to v5: https://lore.kernel.org/r/20250925-sound-v5-0-2593586ff350@uniontech.com

Changes in v5:
- Apply review comments. Thanks a lot, Takashi Iwai!
- Link to v4: https://lore.kernel.org/r/20250918-sound-v4-0-82cf8123d61c@uniontech.com

Changes in v4:
- Split basic parse and dynamic change
- Drop usage of linked list
- Link to v3: https://lore.kernel.org/r/20250917-sound-v3-0-92ebe9472a0a@uniontech.com

Changes in v3:
- Instead of a new param, improve the existed one.
- Link to v2: https://lore.kernel.org/r/20250912-sound-v2-0-01ea3d279f4b@uniontech.com

Changes in v2:
- Cleaned up some internal rebase confusion, sorry for that
- Link to v1: https://lore.kernel.org/r/20250912-sound-v1-0-cc9cfd9f2d01@uniontech.com

---
Cryolitia PukNgae (4):
      ALSA: usb-audio: add two-way convert between name and bit for QUIRK_FLAG_*
      ALSA: usb-audio: improve module param quirk_flags
      ALSA: usb-audio: make param quirk_flags change-able in runtime
      ALSA: doc: improved docs about quirk_flags in snd-usb-audio

 Documentation/sound/alsa-configuration.rst | 108 ++++++++++++------
 sound/usb/card.c                           |  55 +++++++--
 sound/usb/quirks.c                         | 173 ++++++++++++++++++++++++++++-
 sound/usb/quirks.h                         |  11 +-
 sound/usb/usbaudio.h                       |  84 +++++++++-----
 5 files changed, 359 insertions(+), 72 deletions(-)
---
base-commit: 4c421c40c8b30ab7aae1edc7f7e294fcd33fc186
change-id: 20250910-sound-a91c86c92dba

Best regards,
-- 
Cryolitia PukNgae <cryolitia@uniontech.com>

[PATCH v6 1/4] ALSA: usb-audio: add two-way convert between name and bit for QUIRK_FLAG_*

[Cryolitia PukNgae via B4 Relay]

From: Cryolitia PukNgae <cryolitia@uniontech.com>

Define quirk flags enum and its name.

Add helper for converting between quirk flags' name and bit.
  - snd_usb_quirk_flag_find_name()
  - snd_usb_quirk_flags_from_name()

Add helper for printing debug: log snd_usb_apply_flag_dbg()

Co-developed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Cryolitia PukNgae <cryolitia@uniontech.com>
---
 sound/usb/quirks.c   | 83 ++++++++++++++++++++++++++++++++++++++++++++++++---
 sound/usb/quirks.h   |  7 +++++
 sound/usb/usbaudio.h | 84 ++++++++++++++++++++++++++++++++++++----------------
 3 files changed, 144 insertions(+), 30 deletions(-)

diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index d736a4750356597bfb0f9d5ab01cdaeaac0f907c..def1573f65df91ae26a988a45a10267ffba18739 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -2446,6 +2446,84 @@ static const struct usb_audio_quirk_flags_table quirk_flags_table[] = {
 	{} /* terminator */
 };
 
+#define QUIRK_STRING_ENTRY(x) \
+	[QUIRK_TYPE_ ## x] = __stringify(x)
+
+static const char *const snd_usb_audio_quirk_flag_names[] = {
+	QUIRK_STRING_ENTRY(GET_SAMPLE_RATE),
+	QUIRK_STRING_ENTRY(SHARE_MEDIA_DEVICE),
+	QUIRK_STRING_ENTRY(ALIGN_TRANSFER),
+	QUIRK_STRING_ENTRY(TX_LENGTH),
+	QUIRK_STRING_ENTRY(PLAYBACK_FIRST),
+	QUIRK_STRING_ENTRY(SKIP_CLOCK_SELECTOR),
+	QUIRK_STRING_ENTRY(IGNORE_CLOCK_SOURCE),
+	QUIRK_STRING_ENTRY(ITF_USB_DSD_DAC),
+	QUIRK_STRING_ENTRY(CTL_MSG_DELAY),
+	QUIRK_STRING_ENTRY(CTL_MSG_DELAY_1M),
+	QUIRK_STRING_ENTRY(CTL_MSG_DELAY_5M),
+	QUIRK_STRING_ENTRY(IFACE_DELAY),
+	QUIRK_STRING_ENTRY(VALIDATE_RATES),
+	QUIRK_STRING_ENTRY(DISABLE_AUTOSUSPEND),
+	QUIRK_STRING_ENTRY(IGNORE_CTL_ERROR),
+	QUIRK_STRING_ENTRY(DSD_RAW),
+	QUIRK_STRING_ENTRY(SET_IFACE_FIRST),
+	QUIRK_STRING_ENTRY(GENERIC_IMPLICIT_FB),
+	QUIRK_STRING_ENTRY(SKIP_IMPLICIT_FB),
+	QUIRK_STRING_ENTRY(IFACE_SKIP_CLOSE),
+	QUIRK_STRING_ENTRY(FORCE_IFACE_RESET),
+	QUIRK_STRING_ENTRY(FIXED_RATE),
+	QUIRK_STRING_ENTRY(MIC_RES_16),
+	QUIRK_STRING_ENTRY(MIC_RES_384),
+	QUIRK_STRING_ENTRY(MIXER_PLAYBACK_MIN_MUTE),
+	QUIRK_STRING_ENTRY(MIXER_CAPTURE_MIN_MUTE),
+	NULL
+};
+
+const char *snd_usb_quirk_flag_find_name(unsigned long index)
+{
+	if (index >= ARRAY_SIZE(snd_usb_audio_quirk_flag_names))
+		return NULL;
+
+	return snd_usb_audio_quirk_flag_names[index];
+}
+
+u32 snd_usb_quirk_flags_from_name(const char *name)
+{
+	int i;
+
+	if (!name || !*name)
+		return 0;
+
+	for (i = 0; snd_usb_audio_quirk_flag_names[i]; i++) {
+		if (strcasecmp(name, snd_usb_audio_quirk_flag_names[i]) == 0)
+			return BIT_U32(i);
+	}
+
+	return 0;
+}
+
+void snd_usb_apply_flag_dbg(const char *reason,
+			    struct snd_usb_audio *chip,
+			    unsigned long flag)
+{
+	unsigned long bit;
+
+	for_each_set_bit(bit, &flag, BYTES_TO_BITS(sizeof(flag))) {
+		const char *name = snd_usb_audio_quirk_flag_names[bit];
+
+		if (name)
+			usb_audio_dbg(chip,
+				      "From %s apply quirk flag %s for device %04x:%04x\n",
+				      reason, name, USB_ID_VENDOR(chip->usb_id),
+				      USB_ID_PRODUCT(chip->usb_id));
+		else
+			usb_audio_warn(chip,
+				       "From %s apply unknown quirk flag 0x%lx for device %04x:%04x\n",
+				       reason, bit, USB_ID_VENDOR(chip->usb_id),
+				       USB_ID_PRODUCT(chip->usb_id));
+	}
+}
+
 void snd_usb_init_quirk_flags(struct snd_usb_audio *chip)
 {
 	const struct usb_audio_quirk_flags_table *p;
@@ -2454,10 +2532,7 @@ void snd_usb_init_quirk_flags(struct snd_usb_audio *chip)
 		if (chip->usb_id == p->id ||
 		    (!USB_ID_PRODUCT(p->id) &&
 		     USB_ID_VENDOR(chip->usb_id) == USB_ID_VENDOR(p->id))) {
-			usb_audio_dbg(chip,
-				      "Set quirk_flags 0x%x for device %04x:%04x\n",
-				      p->flags, USB_ID_VENDOR(chip->usb_id),
-				      USB_ID_PRODUCT(chip->usb_id));
+			snd_usb_apply_flag_dbg("builtin table", chip, p->flags);
 			chip->quirk_flags |= p->flags;
 			return;
 		}
diff --git a/sound/usb/quirks.h b/sound/usb/quirks.h
index f9bfd5ac7bab01717de3a76227482a128bf73165..1b727d3c35c7033b85b56ce43d66fd76c8f2d4ef 100644
--- a/sound/usb/quirks.h
+++ b/sound/usb/quirks.h
@@ -48,6 +48,13 @@ void snd_usb_audioformat_attributes_quirk(struct snd_usb_audio *chip,
 					  struct audioformat *fp,
 					  int stream);
 
+void snd_usb_apply_flag_dbg(const char *reason,
+			    struct snd_usb_audio *chip,
+			    unsigned long flag);
+
 void snd_usb_init_quirk_flags(struct snd_usb_audio *chip);
 
+const char *snd_usb_quirk_flag_find_name(unsigned long flag);
+u32 snd_usb_quirk_flags_from_name(const char *name);
+
 #endif /* __USBAUDIO_QUIRKS_H */
diff --git a/sound/usb/usbaudio.h b/sound/usb/usbaudio.h
index 30b5102e3caed01eeb86d0075c41338104c58950..79978cae9799cd14da2c7d2391df104df40fa672 100644
--- a/sound/usb/usbaudio.h
+++ b/sound/usb/usbaudio.h
@@ -226,31 +226,63 @@ extern bool snd_usb_skip_validation;
  *  Similar to QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE, but for capture streams
  */
 
-#define QUIRK_FLAG_GET_SAMPLE_RATE	(1U << 0)
-#define QUIRK_FLAG_SHARE_MEDIA_DEVICE	(1U << 1)
-#define QUIRK_FLAG_ALIGN_TRANSFER	(1U << 2)
-#define QUIRK_FLAG_TX_LENGTH		(1U << 3)
-#define QUIRK_FLAG_PLAYBACK_FIRST	(1U << 4)
-#define QUIRK_FLAG_SKIP_CLOCK_SELECTOR	(1U << 5)
-#define QUIRK_FLAG_IGNORE_CLOCK_SOURCE	(1U << 6)
-#define QUIRK_FLAG_ITF_USB_DSD_DAC	(1U << 7)
-#define QUIRK_FLAG_CTL_MSG_DELAY	(1U << 8)
-#define QUIRK_FLAG_CTL_MSG_DELAY_1M	(1U << 9)
-#define QUIRK_FLAG_CTL_MSG_DELAY_5M	(1U << 10)
-#define QUIRK_FLAG_IFACE_DELAY		(1U << 11)
-#define QUIRK_FLAG_VALIDATE_RATES	(1U << 12)
-#define QUIRK_FLAG_DISABLE_AUTOSUSPEND	(1U << 13)
-#define QUIRK_FLAG_IGNORE_CTL_ERROR	(1U << 14)
-#define QUIRK_FLAG_DSD_RAW		(1U << 15)
-#define QUIRK_FLAG_SET_IFACE_FIRST	(1U << 16)
-#define QUIRK_FLAG_GENERIC_IMPLICIT_FB	(1U << 17)
-#define QUIRK_FLAG_SKIP_IMPLICIT_FB	(1U << 18)
-#define QUIRK_FLAG_IFACE_SKIP_CLOSE	(1U << 19)
-#define QUIRK_FLAG_FORCE_IFACE_RESET	(1U << 20)
-#define QUIRK_FLAG_FIXED_RATE		(1U << 21)
-#define QUIRK_FLAG_MIC_RES_16		(1U << 22)
-#define QUIRK_FLAG_MIC_RES_384		(1U << 23)
-#define QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE	(1U << 24)
-#define QUIRK_FLAG_MIXER_CAPTURE_MIN_MUTE	(1U << 25)
+enum {
+	QUIRK_TYPE_GET_SAMPLE_RATE		= 0,
+	QUIRK_TYPE_SHARE_MEDIA_DEVICE		= 1,
+	QUIRK_TYPE_ALIGN_TRANSFER		= 2,
+	QUIRK_TYPE_TX_LENGTH			= 3,
+	QUIRK_TYPE_PLAYBACK_FIRST		= 4,
+	QUIRK_TYPE_SKIP_CLOCK_SELECTOR		= 5,
+	QUIRK_TYPE_IGNORE_CLOCK_SOURCE		= 6,
+	QUIRK_TYPE_ITF_USB_DSD_DAC		= 7,
+	QUIRK_TYPE_CTL_MSG_DELAY		= 8,
+	QUIRK_TYPE_CTL_MSG_DELAY_1M		= 9,
+	QUIRK_TYPE_CTL_MSG_DELAY_5M		= 10,
+	QUIRK_TYPE_IFACE_DELAY			= 11,
+	QUIRK_TYPE_VALIDATE_RATES		= 12,
+	QUIRK_TYPE_DISABLE_AUTOSUSPEND		= 13,
+	QUIRK_TYPE_IGNORE_CTL_ERROR		= 14,
+	QUIRK_TYPE_DSD_RAW			= 15,
+	QUIRK_TYPE_SET_IFACE_FIRST		= 16,
+	QUIRK_TYPE_GENERIC_IMPLICIT_FB		= 17,
+	QUIRK_TYPE_SKIP_IMPLICIT_FB		= 18,
+	QUIRK_TYPE_IFACE_SKIP_CLOSE		= 19,
+	QUIRK_TYPE_FORCE_IFACE_RESET		= 20,
+	QUIRK_TYPE_FIXED_RATE			= 21,
+	QUIRK_TYPE_MIC_RES_16			= 22,
+	QUIRK_TYPE_MIC_RES_384			= 23,
+	QUIRK_TYPE_MIXER_PLAYBACK_MIN_MUTE	= 24,
+	QUIRK_TYPE_MIXER_CAPTURE_MIN_MUTE	= 25,
+/* Please also edit snd_usb_audio_quirk_flag_names */
+};
+
+#define QUIRK_FLAG(x)	BIT_U32(QUIRK_TYPE_ ## x)
+
+#define QUIRK_FLAG_GET_SAMPLE_RATE		QUIRK_FLAG(GET_SAMPLE_RATE)
+#define QUIRK_FLAG_SHARE_MEDIA_DEVICE		QUIRK_FLAG(SHARE_MEDIA_DEVICE)
+#define QUIRK_FLAG_ALIGN_TRANSFER		QUIRK_FLAG(ALIGN_TRANSFER)
+#define QUIRK_FLAG_TX_LENGTH			QUIRK_FLAG(TX_LENGTH)
+#define QUIRK_FLAG_PLAYBACK_FIRST		QUIRK_FLAG(PLAYBACK_FIRST)
+#define QUIRK_FLAG_SKIP_CLOCK_SELECTOR		QUIRK_FLAG(SKIP_CLOCK_SELECTOR)
+#define QUIRK_FLAG_IGNORE_CLOCK_SOURCE		QUIRK_FLAG(IGNORE_CLOCK_SOURCE)
+#define QUIRK_FLAG_ITF_USB_DSD_DAC		QUIRK_FLAG(ITF_USB_DSD_DAC)
+#define QUIRK_FLAG_CTL_MSG_DELAY		QUIRK_FLAG(CTL_MSG_DELAY)
+#define QUIRK_FLAG_CTL_MSG_DELAY_1M		QUIRK_FLAG(CTL_MSG_DELAY_1M)
+#define QUIRK_FLAG_CTL_MSG_DELAY_5M		QUIRK_FLAG(CTL_MSG_DELAY_5M)
+#define QUIRK_FLAG_IFACE_DELAY			QUIRK_FLAG(IFACE_DELAY)
+#define QUIRK_FLAG_VALIDATE_RATES		QUIRK_FLAG(VALIDATE_RATES)
+#define QUIRK_FLAG_DISABLE_AUTOSUSPEND		QUIRK_FLAG(DISABLE_AUTOSUSPEND)
+#define QUIRK_FLAG_IGNORE_CTL_ERROR		QUIRK_FLAG(IGNORE_CTL_ERROR)
+#define QUIRK_FLAG_DSD_RAW			QUIRK_FLAG(DSD_RAW)
+#define QUIRK_FLAG_SET_IFACE_FIRST		QUIRK_FLAG(SET_IFACE_FIRST)
+#define QUIRK_FLAG_GENERIC_IMPLICIT_FB		QUIRK_FLAG(GENERIC_IMPLICIT_FB)
+#define QUIRK_FLAG_SKIP_IMPLICIT_FB		QUIRK_FLAG(SKIP_IMPLICIT_FB)
+#define QUIRK_FLAG_IFACE_SKIP_CLOSE		QUIRK_FLAG(IFACE_SKIP_CLOSE)
+#define QUIRK_FLAG_FORCE_IFACE_RESET		QUIRK_FLAG(FORCE_IFACE_RESET)
+#define QUIRK_FLAG_FIXED_RATE			QUIRK_FLAG(FIXED_RATE)
+#define QUIRK_FLAG_MIC_RES_16			QUIRK_FLAG(MIC_RES_16)
+#define QUIRK_FLAG_MIC_RES_384			QUIRK_FLAG(MIC_RES_384)
+#define QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE	QUIRK_FLAG(MIXER_PLAYBACK_MIN_MUTE)
+#define QUIRK_FLAG_MIXER_CAPTURE_MIN_MUTE	QUIRK_FLAG(MIXER_CAPTURE_MIN_MUTE)
 
 #endif /* __USBAUDIO_H */

-- 
2.51.0

[PATCH v6 2/4] ALSA: usb-audio: improve module param quirk_flags

[Cryolitia PukNgae via B4 Relay]

From: Cryolitia PukNgae <cryolitia@uniontech.com>

It accepts strings like `VID:PID:quirk_flag_name1|quirk_flag_name2;...`
from now on, so that we can use it to debug USB audio devices more
intuitive and flexible. The compatibility of previous form is kept.

Co-developed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Cryolitia PukNgae <cryolitia@uniontech.com>
---
 sound/usb/card.c   | 32 +++++++++++++++----
 sound/usb/quirks.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
 sound/usb/quirks.h |  4 ++-
 3 files changed, 118 insertions(+), 8 deletions(-)

diff --git a/sound/usb/card.c b/sound/usb/card.c
index 0265206a8e8cf31133e8463c98fe0497d8ace89e..66c6c92fa9e8d2d04cc297a3dc8de9c8a2e99465 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -73,7 +73,7 @@ static bool lowlatency = true;
 static char *quirk_alias[SNDRV_CARDS];
 static char *delayed_register[SNDRV_CARDS];
 static bool implicit_fb[SNDRV_CARDS];
-static unsigned int quirk_flags[SNDRV_CARDS];
+static char *quirk_flags[SNDRV_CARDS];
 
 bool snd_usb_use_vmalloc = true;
 bool snd_usb_skip_validation;
@@ -103,7 +103,7 @@ module_param_array(delayed_register, charp, NULL, 0444);
 MODULE_PARM_DESC(delayed_register, "Quirk for delayed registration, given by id:iface, e.g. 0123abcd:4.");
 module_param_array(implicit_fb, bool, NULL, 0444);
 MODULE_PARM_DESC(implicit_fb, "Apply generic implicit feedback sync mode.");
-module_param_array(quirk_flags, uint, NULL, 0444);
+module_param_array(quirk_flags, charp, NULL, 0444);
 MODULE_PARM_DESC(quirk_flags, "Driver quirk bit flags.");
 module_param_named(use_vmalloc, snd_usb_use_vmalloc, bool, 0444);
 MODULE_PARM_DESC(use_vmalloc, "Use vmalloc for PCM intermediate buffers (default: yes).");
@@ -692,6 +692,29 @@ static void usb_audio_make_longname(struct usb_device *dev,
 	}
 }
 
+static void snd_usb_init_quirk_flags(int idx, struct snd_usb_audio *chip)
+{
+	size_t i;
+
+	/* old style option found: the position-based integer value */
+	if (quirk_flags[idx] &&
+	    !kstrtou32(quirk_flags[idx], 0, &chip->quirk_flags)) {
+		snd_usb_apply_flag_dbg("module param", chip, chip->quirk_flags);
+		return;
+	}
+
+	/* take the default quirk from the quirk table */
+	snd_usb_init_quirk_flags_table(chip);
+
+	/* add or correct quirk bits from options */
+	for (i = 0; i < ARRAY_SIZE(quirk_flags); i++) {
+		if (!quirk_flags[i] || !*quirk_flags[i])
+			break;
+
+		snd_usb_init_quirk_flags_parse_string(chip, quirk_flags[i]);
+	}
+}
+
 /*
  * create a chip instance and set its names.
  */
@@ -750,10 +773,7 @@ static int snd_usb_audio_create(struct usb_interface *intf,
 	INIT_LIST_HEAD(&chip->midi_v2_list);
 	INIT_LIST_HEAD(&chip->mixer_list);
 
-	if (quirk_flags[idx])
-		chip->quirk_flags = quirk_flags[idx];
-	else
-		snd_usb_init_quirk_flags(chip);
+	snd_usb_init_quirk_flags(idx, chip);
 
 	card->private_free = snd_usb_audio_free;
 
diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index def1573f65df91ae26a988a45a10267ffba18739..e7ba25f3df9ec2837744ca6d6fa33791e7893842 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -2524,7 +2524,7 @@ void snd_usb_apply_flag_dbg(const char *reason,
 	}
 }
 
-void snd_usb_init_quirk_flags(struct snd_usb_audio *chip)
+void snd_usb_init_quirk_flags_table(struct snd_usb_audio *chip)
 {
 	const struct usb_audio_quirk_flags_table *p;
 
@@ -2538,3 +2538,91 @@ void snd_usb_init_quirk_flags(struct snd_usb_audio *chip)
 		}
 	}
 }
+
+void snd_usb_init_quirk_flags_parse_string(struct snd_usb_audio *chip,
+					   const char *str)
+{
+	u16 chip_vid = USB_ID_VENDOR(chip->usb_id);
+	u16 chip_pid = USB_ID_PRODUCT(chip->usb_id);
+	u32 mask_flags, unmask_flags, bit;
+	char *p, *field, *flag;
+	bool is_unmask;
+	u16 vid, pid;
+
+	char *val __free(kfree) = kstrdup(str, GFP_KERNEL);
+
+	if (!val)
+		return;
+
+	for (p = val; p && *p;) {
+		/* Each entry consists of VID:PID:flags */
+		field = strsep(&p, ":");
+		if (!field)
+			break;
+
+		if (strcmp(field, "*") == 0)
+			vid = 0;
+		else if (kstrtou16(field, 16, &vid))
+			break;
+
+		field = strsep(&p, ":");
+		if (!field)
+			break;
+
+		if (strcmp(field, "*") == 0)
+			pid = 0;
+		else if (kstrtou16(field, 16, &pid))
+			break;
+
+		field = strsep(&p, ";");
+		if (!field || !*field)
+			break;
+
+		if ((vid != 0 && vid != chip_vid) ||
+		    (pid != 0 && pid != chip_pid))
+			continue;
+
+		/* Collect the flags */
+		mask_flags = 0;
+		unmask_flags = 0;
+		while (field && *field) {
+			flag = strsep(&field, "|");
+
+			if (!flag)
+				break;
+
+			if (*flag == '!') {
+				is_unmask = true;
+				flag++;
+			} else {
+				is_unmask = false;
+			}
+
+			if (!kstrtou32(flag, 16, &bit)) {
+				if (is_unmask)
+					unmask_flags |= bit;
+				else
+					mask_flags |= bit;
+
+				break;
+			}
+
+			bit = snd_usb_quirk_flags_from_name(flag);
+
+			if (bit) {
+				if (is_unmask)
+					unmask_flags |= bit;
+				else
+					mask_flags |= bit;
+			} else {
+				pr_warn("snd_usb_audio: unknown flag %s while parsing param quirk_flags\n",
+					flag);
+			}
+		}
+
+		chip->quirk_flags &= ~unmask_flags;
+		chip->quirk_flags |= mask_flags;
+		snd_usb_apply_flag_dbg("module param", chip,
+				       chip->quirk_flags);
+	}
+}
diff --git a/sound/usb/quirks.h b/sound/usb/quirks.h
index 1b727d3c35c7033b85b56ce43d66fd76c8f2d4ef..f24d6a5a197a641dac36eb3c6eca5dbf5076b495 100644
--- a/sound/usb/quirks.h
+++ b/sound/usb/quirks.h
@@ -52,7 +52,9 @@ void snd_usb_apply_flag_dbg(const char *reason,
 			    struct snd_usb_audio *chip,
 			    unsigned long flag);
 
-void snd_usb_init_quirk_flags(struct snd_usb_audio *chip);
+void snd_usb_init_quirk_flags_table(struct snd_usb_audio *chip);
+void snd_usb_init_quirk_flags_parse_string(struct snd_usb_audio *chip,
+					   const char *str);
 
 const char *snd_usb_quirk_flag_find_name(unsigned long flag);
 u32 snd_usb_quirk_flags_from_name(const char *name);

-- 
2.51.0

[PATCH v6 3/4] ALSA: usb-audio: make param quirk_flags change-able in runtime

[Cryolitia PukNgae via B4 Relay]

From: Cryolitia PukNgae <cryolitia@uniontech.com>

Change its permision from 0644 to 0444, and add runtime processing.

Developers now can change it during sysfs, without rebooting, for
debugging new buggy devices.

Co-developed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Cryolitia PukNgae <cryolitia@uniontech.com>
---
 sound/usb/card.c | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/sound/usb/card.c b/sound/usb/card.c
index 66c6c92fa9e8d2d04cc297a3dc8de9c8a2e99465..1d5a65eac9335028cfeabd2d80b389e364477387 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -103,13 +103,32 @@ module_param_array(delayed_register, charp, NULL, 0444);
 MODULE_PARM_DESC(delayed_register, "Quirk for delayed registration, given by id:iface, e.g. 0123abcd:4.");
 module_param_array(implicit_fb, bool, NULL, 0444);
 MODULE_PARM_DESC(implicit_fb, "Apply generic implicit feedback sync mode.");
-module_param_array(quirk_flags, charp, NULL, 0444);
-MODULE_PARM_DESC(quirk_flags, "Driver quirk bit flags.");
 module_param_named(use_vmalloc, snd_usb_use_vmalloc, bool, 0444);
 MODULE_PARM_DESC(use_vmalloc, "Use vmalloc for PCM intermediate buffers (default: yes).");
 module_param_named(skip_validation, snd_usb_skip_validation, bool, 0444);
 MODULE_PARM_DESC(skip_validation, "Skip unit descriptor validation (default: no).");
 
+/* protects quirk_flags */
+static DEFINE_MUTEX(quirk_flags_mutex);
+
+static int param_set_quirkp(const char *val,
+			    const struct kernel_param *kp)
+{
+	guard(mutex)(&quirk_flags_mutex);
+	return param_set_charp(val, kp);
+}
+
+static const struct kernel_param_ops param_ops_quirkp = {
+	.set = param_set_quirkp,
+	.get = param_get_charp,
+	.free = param_free_charp,
+};
+
+#define param_check_quirkp param_check_charp
+
+module_param_array(quirk_flags, quirkp, NULL, 0644);
+MODULE_PARM_DESC(quirk_flags, "Add/modify USB audio quirks");
+
 /*
  * we keep the snd_usb_audio_t instances by ourselves for merging
  * the all interfaces on the same card as one sound device.
@@ -696,6 +715,8 @@ static void snd_usb_init_quirk_flags(int idx, struct snd_usb_audio *chip)
 {
 	size_t i;
 
+	guard(mutex)(&quirk_flags_mutex);
+
 	/* old style option found: the position-based integer value */
 	if (quirk_flags[idx] &&
 	    !kstrtou32(quirk_flags[idx], 0, &chip->quirk_flags)) {

-- 
2.51.0

[PATCH v6 4/4] ALSA: doc: improved docs about quirk_flags in snd-usb-audio

[Cryolitia PukNgae via B4 Relay]

From: Cryolitia PukNgae <cryolitia@uniontech.com>

Just briefly described about the option's change and its new usage.

Signed-off-by: Cryolitia PukNgae <cryolitia@uniontech.com>
---
 Documentation/sound/alsa-configuration.rst | 108 ++++++++++++++++++++---------
 1 file changed, 75 insertions(+), 33 deletions(-)

diff --git a/Documentation/sound/alsa-configuration.rst b/Documentation/sound/alsa-configuration.rst
index a2fb8ed251dd0294e7a62209ca15d5c32c6adfae..0a4eaa7d66ddd05e7c7378596a351bb6ea17f9ba 100644
--- a/Documentation/sound/alsa-configuration.rst
+++ b/Documentation/sound/alsa-configuration.rst
@@ -2297,39 +2297,81 @@ skip_validation
     of the unit descriptor instead of a driver probe error, so that we
     can check its details.
 quirk_flags
-    Contains the bit flags for various device specific workarounds.
-    Applied to the corresponding card index.
-
-        * bit 0: Skip reading sample rate for devices
-        * bit 1: Create Media Controller API entries
-        * bit 2: Allow alignment on audio sub-slot at transfer
-        * bit 3: Add length specifier to transfers
-        * bit 4: Start playback stream at first in implement feedback mode
-        * bit 5: Skip clock selector setup
-        * bit 6: Ignore errors from clock source search
-        * bit 7: Indicates ITF-USB DSD based DACs
-        * bit 8: Add a delay of 20ms at each control message handling
-        * bit 9: Add a delay of 1-2ms at each control message handling
-        * bit 10: Add a delay of 5-6ms at each control message handling
-        * bit 11: Add a delay of 50ms at each interface setup
-        * bit 12: Perform sample rate validations at probe
-        * bit 13: Disable runtime PM autosuspend
-        * bit 14: Ignore errors for mixer access
-        * bit 15: Support generic DSD raw U32_BE format
-        * bit 16: Set up the interface at first like UAC1
-        * bit 17: Apply the generic implicit feedback sync mode
-        * bit 18: Don't apply implicit feedback sync mode
-        * bit 19: Don't closed interface during setting sample rate
-        * bit 20: Force an interface reset whenever stopping & restarting
-          a stream
-        * bit 21: Do not set PCM rate (frequency) when only one rate is
-          available for the given endpoint.
-        * bit 22: Set the fixed resolution 16 for Mic Capture Volume
-        * bit 23: Set the fixed resolution 384 for Mic Capture Volume
-        * bit 24: Set minimum volume control value as mute for devices
-          where the lowest playback value represents muted state instead
-          of minimum audible volume
-        * bit 25: Be similar to bit 24 but for capture streams
+    The option provides a refined and flexible control for applying quirk
+    flags.  It allows to specify the quirk flags for each device, and can
+    be modified dynamically via sysfs.
+    The old usage accepts an array of integers, each of which applies quirk
+    flags on the device in the order of probing.
+    E.g., ``quirk_flags=0x01,0x02`` applies get_sample_rate to the first
+    device, and share_media_device to the second device.
+    The new usage accepts a string in the format of
+    ``VID1:PID1:FLAGS1;VID2:PID2:FLAGS2;...``, where ``VIDx`` and ``PIDx``
+    specify the device, and ``FLAGSx`` specify the flags to be applied.
+    ``VIDx`` and ``PIDx`` are 4-digit hexadecimal numbers, and can be
+    specified as ``*`` to match any value.  ``FLAGSx`` can be a set of
+    flags given by name, separated by ``|``, or a hexadecimal number
+    representing the bit flags.  The available flag names are listed below.
+    An exclamation mark can be prefixed to a flag name to negate the flag.
+    For example, ``1234:abcd:mixer_playback_min_mute|!ignore_ctl_error;*:*:0x01;``
+    applies the ``mixer_playback_min_mute`` flag and clears the
+    ``ignore_ctl_error`` flag for the device 1234:abcd, and applies the
+    ``skip_sample_rate`` flag for all devices.
+
+        * bit 0: ``get_sample_rate``
+          Skip reading sample rate for devices
+        * bit 1: ``share_media_device``
+          Create Media Controller API entries
+        * bit 2: ``align_transfer``
+          Allow alignment on audio sub-slot at transfer
+        * bit 3: ``tx_length``
+          Add length specifier to transfers
+        * bit 4: ``playback_first``
+          Start playback stream at first in implement feedback mode
+        * bit 5: ``skip_clock_selector``
+          Skip clock selector setup
+        * bit 6: ``ignore_clock_source``
+          Ignore errors from clock source search
+        * bit 7: ``itf_usb_dsd_dac``
+          Indicates ITF-USB DSD-based DACs
+        * bit 8: ``ctl_msg_delay``
+          Add a delay of 20ms at each control message handling
+        * bit 9: ``ctl_msg_delay_1m``
+          Add a delay of 1-2ms at each control message handling
+        * bit 10: ``ctl_msg_delay_5m``
+          Add a delay of 5-6ms at each control message handling
+        * bit 11: ``iface_delay``
+          Add a delay of 50ms at each interface setup
+        * bit 12: ``validate_rates``
+          Perform sample rate validations at probe
+        * bit 13: ``disable_autosuspend``
+          Disable runtime PM autosuspend
+        * bit 14: ``ignore_ctl_error``
+          Ignore errors for mixer access
+        * bit 15: ``dsd_raw``
+          Support generic DSD raw U32_BE format
+        * bit 16: ``set_iface_first``
+          Set up the interface at first like UAC1
+        * bit 17: ``generic_implicit_fb``
+          Apply the generic implicit feedback sync mode
+        * bit 18: ``skip_implicit_fb``
+          Don't apply implicit feedback sync mode
+        * bit 19: ``iface_skip_close``
+          Don't close interface during setting sample rate
+        * bit 20: ``force_iface_reset``
+          Force an interface reset whenever stopping & restarting a stream
+        * bit 21: ``fixed_rate``
+          Do not set PCM rate (frequency) when only one rate is available
+          for the given endpoint
+        * bit 22: ``mic_res_16``
+          Set the fixed resolution 16 for Mic Capture Volume
+        * bit 23: ``mic_res_384``
+          Set the fixed resolution 384 for Mic Capture Volume
+        * bit 24: ``mixer_playback_min_mute``
+          Set minimum volume control value as mute for devices where the
+          lowest playback value represents muted state instead of minimum
+          audible volume
+        * bit 25: ``mixer_capture_min_mute``
+          Similar to bit 24 but for capture streams
 
 This module supports multiple devices, autoprobe and hotplugging.
 

-- 
2.51.0

Re: [PATCH v6 0/4] ALSA: usb-audio: improve module param quirk_flags

[Takashi Iwai]

On Sun, 28 Sep 2025 05:07:58 +0200,
Cryolitia PukNgae via B4 Relay wrote:
> 
> As an implementation of what has been discussed previously[1].
> 
> 1. https://lore.kernel.org/all/87h5xm5g7f.wl-tiwai@suse.de/
> 
> Signed-off-by: Cryolitia PukNgae <cryolitia@uniontech.com>
> ---
> Changes in v6:
> - Apply review commens, details corrected and wording revised
> - Link to v5: https://lore.kernel.org/r/20250925-sound-v5-0-2593586ff350@uniontech.com
> 
> Changes in v5:
> - Apply review comments. Thanks a lot, Takashi Iwai!
> - Link to v4: https://lore.kernel.org/r/20250918-sound-v4-0-82cf8123d61c@uniontech.com
> 
> Changes in v4:
> - Split basic parse and dynamic change
> - Drop usage of linked list
> - Link to v3: https://lore.kernel.org/r/20250917-sound-v3-0-92ebe9472a0a@uniontech.com
> 
> Changes in v3:
> - Instead of a new param, improve the existed one.
> - Link to v2: https://lore.kernel.org/r/20250912-sound-v2-0-01ea3d279f4b@uniontech.com
> 
> Changes in v2:
> - Cleaned up some internal rebase confusion, sorry for that
> - Link to v1: https://lore.kernel.org/r/20250912-sound-v1-0-cc9cfd9f2d01@uniontech.com
> 
> ---
> Cryolitia PukNgae (4):
>       ALSA: usb-audio: add two-way convert between name and bit for QUIRK_FLAG_*
>       ALSA: usb-audio: improve module param quirk_flags
>       ALSA: usb-audio: make param quirk_flags change-able in runtime
>       ALSA: doc: improved docs about quirk_flags in snd-usb-audio

Now applied all four patches.  Thanks!


Takashi