[PATCH 0/2] ALSA: usb-audio: Fix stale quirk control caches after write failures

[Cássio Gabriel]

This series fixes stale software cache handling in several usb-audio
mixer quirks.

A number of quirk callbacks update kcontrol->private_value before
issuing vendor or class writes. When such a write fails, the driver can
keep reporting and later replaying a value the device never accepted,
because the corresponding get and resume paths consume the cached state.

- Patch 1 fixes the simple single-write quirk callbacks by restoring the
  previous cache on error.
- Patch 2 fixes the RME Babyface Pro packed-state callbacks by updating
  the cache only after a successful write, since those helpers already
  take explicit arguments and do not need private_value to be updated
  before the USB request.

The split keeps the generic quirk fixes separate from the Babyface Pro
packed-state logic and keeps each patch tied to its own introducing bug.

Signed-off-by: Cássio Gabriel <cassiogabrielcontato@xxxxxxxxx>
---
Cássio Gabriel (2):
      ALSA: usb-audio: Roll back quirk control caches on write errors
      ALSA: usb-audio: Update Babyface Pro control caches only after successful writes

 sound/usb/mixer_quirks.c | 61 +++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 47 insertions(+), 14 deletions(-)
---
base-commit: 7b04e87c2a10db9c65b3133949bbe1b738b6ed7e
change-id: 20260418-alsa-usb-quirks-cache-rollback-43a07052f22c

Best regards,
--  
Cássio Gabriel <cassiogabrielcontato@xxxxxxxxx>