Re: [PATCH] ALSA: hda/tas2781: Wait for async firmware callback at unbind

[Takashi Iwai <tiwai@suse.de>]

On Thu, 30 Apr 2026 06:02:02 +0200,
Cássio Gabriel wrote:
> 
> The TAS2781 HDA I2C and SPI side-codec drivers queue the RCA
> firmware load with request_firmware_nowait() from component bind. The
> firmware loader keeps a device reference and pins the callback module,
> but it does not protect the driver's HDA private state from component
> unbind.
> 
> The callback dereferences tas_hda/tas_priv, takes codec_lock,
> creates ALSA controls, updates RCA/DSP state, runs runtime PM, and may
> load DSP and calibration data. Component unbind currently removes
> controls and DSP state immediately, and the later device remove destroys
> codec_lock through tasdevice_remove(). A delayed callback can therefore
> run after the HDA component state has been torn down.
> 
> Track the pending HDA RCA request with a completion. Mark it cancelled
> at unbind, let a callback that observes cancellation exit before parsing
> firmware or creating controls, and wait for any already-running callback
> before tearing down HDA controls and DSP state.
> 
> Clear cached kcontrol pointers as controls are removed, and when
> snd_ctl_add() rejects them, so a later cancelled or failed bind cannot
> remove stale controls from an earlier bind.
> 
> Fixes: 5be27f1e3ec9 ("ALSA: hda/tas2781: Add tas2781 HDA driver")
> Fixes: bb5f86ea50ff ("ALSA: hda/tas2781: Add tas2781 hda SPI driver")
> Cc: stable@vger.kernel.org
> Signed-off-by: Cássio Gabriel <cassiogabrielcontato@gmail.com>

Hmm, this looks too complex than needed.  Basically what we want is a
simple cancel or sync for async firmware loading work.  Once when such
a helper is provided, the rest in the HD-audio side will be just a
call of it at the remove or unbind.  And, I guess we can implement the
helper in the f/w loader with a help of devres or such.


thanks,

Takashi