[PATCH v3 0/2] firmware_loader/ALSA: Fix TAS2781 async firmware teardown

[Cássio Gabriel]

TAS2781 HDA I2C and SPI queue RCA firmware loading with
request_firmware_nowait() during component bind. The firmware loader
keeps the callback module pinned and holds a device reference, but it
does not provide a way for drivers to cancel or synchronize the queued
callback before tearing down driver-private state.

Add a small firmware-loader helper to cancel or synchronize async firmware
requests, then use it from TAS2781 HDA unbind before controls and DSP state
are removed.

No hardware runtime test was available.

---
Changes in v3:
- Keep request_firmware_nowait() manually managed instead of making the
  existing API implicitly devres-managed.
- Track scheduled async firmware work in an internal list protected by a
  spinlock so request_firmware_nowait_cancel() can find and synchronize a
  pending request without weakening the GFP_ATOMIC caller contract.
- Match pending requests by device, callback context and callback function
  instead of matching by callback alone.
- Avoid the devres_add() / schedule_work() ordering race pointed out in
  review.
- Leave devres-managed support for a separate devm_request_firmware_nowait()
  API if needed.
- Link to v2: https://patch.msgid.link/20260430-alsa-hda-tas2781-fw-callback-teardown-v2-0-2c7d89cb3175@xxxxxxxxx

Changes in v2:
- Add request_firmware_nowait_cancel() in the firmware loader instead of
  tracking the callback lifetime locally in the TAS2781 HDA driver.
- Keep the TAS2781 change to a cancel/sync call in I2C and SPI unbind.
- Drop the unrelated cached kcontrol pointer cleanup from the previous
  local-driver version.
- Link to v1: https://patch.msgid.link/20260430-alsa-hda-tas2781-fw-callback-teardown-v1-1-874367d6b41b@xxxxxxxxx

To: Luis Chamberlain <mcgrof@xxxxxxxxxx>
To: Russ Weight <russ.weight@xxxxxxxxx>
To: Danilo Krummrich <dakr@xxxxxxxxxx>
To: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
To: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
To: Takashi Iwai <tiwai@xxxxxxxx>
To: Shenghao Ding <shenghao-ding@xxxxxx>
To: Kevin Lu <kevin-lu@xxxxxx>
To: Baojun Xu <baojun.xu@xxxxxx>
To: Jaroslav Kysela <perex@xxxxxxxx>
Cc: driver-core@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-sound@xxxxxxxxxxxxxxx
Signed-off-by: Cássio Gabriel <cassiogabrielcontato@xxxxxxxxx>

---
Cássio Gabriel (2):
      firmware_loader: Add cancel helper for async requests
      ALSA: hda/tas2781: Cancel async firmware request at unbind

 drivers/base/firmware_loader/main.c            | 71 ++++++++++++++++++++++++--
 include/linux/firmware.h                       | 10 ++++
 sound/hda/codecs/side-codecs/tas2781_hda_i2c.c |  3 ++
 sound/hda/codecs/side-codecs/tas2781_hda_spi.c |  3 ++
 4 files changed, 83 insertions(+), 4 deletions(-)
---
base-commit: 1bc46462f4c09f8d429ae8ec17f92886d604659f
change-id: 20260421-alsa-hda-tas2781-fw-callback-teardown-3b76404bb928

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