[PATCH v4 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.

Signed-off-by: Cássio Gabriel <cassiogabrielcontato@xxxxxxxxx>
---
Changes in v4:
- Use spin_lock_irq() in the worker and cancel paths, which run from
  sleepable contexts.
- Fold kfree(fw_work) into firmware_work_free().
- Keep irqsave in the request path so GFP_ATOMIC callers do not depend on
  IRQ state assumptions.
- Link to v3: https://patch.msgid.link/20260501-alsa-hda-tas2781-fw-callback-teardown-v3-0-8d9f873b97bd@xxxxxxxxx

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

---
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            | 68 ++++++++++++++++++++++++--
 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, 80 insertions(+), 4 deletions(-)
---
base-commit: 0d672ef050d4e1c3891c9944f72c85769978bbee
change-id: 20260421-alsa-hda-tas2781-fw-callback-teardown-3b76404bb928

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