[PATCH AUTOSEL 6.19-5.15] ALSA: usb-audio: Add iface reset and delay quirk for AB13X USB Audio

[Sasha Levin <sashal@kernel.org>]

From: Lianqin Hu <hulianqin@vivo.com>

[ Upstream commit ac656d7d7c70f7c352c7652bc2bb0c1c8c2dde08 ]

Setting up the interface when suspended/resumeing fail on this card.
Adding a reset and delay quirk will eliminate this problem.

usb 1-1: New USB device found, idVendor=001f, idProduct=0b21
usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 1-1: Product: AB13X USB Audio
usb 1-1: Manufacturer: Generic
usb 1-1: SerialNumber: 20210926172016

Signed-off-by: Lianqin Hu <hulianqin@vivo.com>
Link: https://patch.msgid.link/TYUPR06MB6217522D0DB6E2C9DF46B56ED265A@TYUPR06MB6217.apcprd06.prod.outlook.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

LLM Generated explanations, may be completely bogus:

## Analysis of ALSA: usb-audio: Add iface reset and delay quirk for
AB13X USB Audio

### Commit Message Analysis

The commit message clearly describes a **suspend/resume failure** on the
AB13X USB Audio device (vendor 0x001f, product 0x0b21). The fix adds two
quirk flags (`QUIRK_FLAG_FORCE_IFACE_RESET` and
`QUIRK_FLAG_IFACE_DELAY`) to work around the hardware's broken behavior
during interface setup on suspend/resume cycles.

### Code Change Analysis

The change is a **two-line addition** (plus a comment) to the
`quirk_flags_table[]` array in `sound/usb/quirks.c`:

```c
DEVICE_FLG(0x001f, 0x0b21, /* AB13X USB Audio */
           QUIRK_FLAG_FORCE_IFACE_RESET | QUIRK_FLAG_IFACE_DELAY),
```

This is inserted in the correct sorted position (by vendor ID) in the
existing quirk flags table. The quirk flags
`QUIRK_FLAG_FORCE_IFACE_RESET` and `QUIRK_FLAG_IFACE_DELAY` are pre-
existing flags already used by other devices in the table — no new
infrastructure is introduced.

### Classification: Hardware Quirk

This falls squarely into the **hardware quirks/workarounds** exception
category for stable backporting:

- **It uses existing quirk infrastructure** — the flags and the table
  mechanism already exist in the kernel
- **It targets a specific device** (USB vendor 0x001f, product 0x0b21) —
  zero risk to any other device
- **It fixes a real user-facing bug** — suspend/resume failure means the
  audio device stops working after a laptop suspends and resumes, which
  is a common operation for laptop users
- **The pattern is identical to many other entries** in the same table
  (e.g., the HP 320 FHD Webcam, Creative SB Extigy, MS USB Link headset,
  etc.)

### Scope and Risk Assessment

- **Lines changed**: 2 (plus comment) — trivially small
- **Files touched**: 1 (`sound/usb/quirks.c`)
- **Risk**: Essentially zero — this only activates for the specific USB
  device ID 0x001f:0x0b21, and the quirk flags are well-tested
  mechanisms used by many other devices
- **Dependencies**: None — the quirk flags and table infrastructure have
  existed for a long time in stable kernels

### User Impact

- **Who is affected**: Users with the AB13X USB Audio device (Generic
  brand, manufactured 2021+)
- **Severity without fix**: Audio device fails on suspend/resume — a
  significant usability problem for laptop users
- **Severity of fix**: Adds a reset and delay during interface setup,
  which is a standard workaround for USB audio devices with timing
  issues

### Stability Indicators

- Accepted by Takashi Iwai (ALSA maintainer) — the subsystem maintainer
  reviewed and merged this
- The same quirk pattern is used by dozens of other devices in the same
  table with no issues
- The change is data-only (adding an entry to a table) with no logic
  changes

### Conclusion

This is a textbook example of a **hardware quirk addition** that belongs
in stable trees. It:
1. Fixes a real bug (suspend/resume failure)
2. Is obviously correct (uses existing, well-tested quirk
   infrastructure)
3. Is tiny and self-contained (2-line table entry addition)
4. Has zero risk of regression (device-specific, no logic changes)
5. Has no dependencies on other commits

**YES**

 sound/usb/quirks.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index d550c84e7752f..9fb823b11caaa 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -2147,6 +2147,8 @@ struct usb_audio_quirk_flags_table {
 
 static const struct usb_audio_quirk_flags_table quirk_flags_table[] = {
 	/* Device matches */
+	DEVICE_FLG(0x001f, 0x0b21, /* AB13X USB Audio */
+		   QUIRK_FLAG_FORCE_IFACE_RESET | QUIRK_FLAG_IFACE_DELAY),
 	DEVICE_FLG(0x03f0, 0x654a, /* HP 320 FHD Webcam */
 		   QUIRK_FLAG_GET_SAMPLE_RATE | QUIRK_FLAG_MIC_RES_16),
 	DEVICE_FLG(0x041e, 0x3000, /* Creative SB Extigy */
-- 
2.51.0