Re: [PATCH v3] ALSA: hda: Reset response counter when a verb times out

[Takashi Iwai <tiwai@suse.de>]

On Sat, 10 Oct 2026 10:27:24 +0200,
songxiebing wrote:
> 
> From: Bob Song <songxiebing@kylinos.cn>
> 
> On some controllers the HDA link reports a verb timeout and the driver
> falls back to polling mode.  After that, every subsequent verb sent to
> that codec address keeps timing out (roughly one second per verb), while
> the hardware itself looks perfectly healthy: the RIRB write pointer keeps
> advancing, interrupts are still delivered, and verbs that carry no reply
> payload -- notably writes -- still take effect on the codec.
> 
> The reason is that bus->rirb.cmds[addr] is incremented for every verb and
> only decremented in snd_hdac_bus_update_rirb() when a matching RIRB
> response is read, without any rollback for a response that never arrives.
> A controller that cannot fall back to the single-command mode
> (chip->fallback_to_single_cmd == 0, e.g. the ACPI platform, Tegra and CIX
> controllers) returns an error right away and never performs the bus reset
> that would reinitialize CORB/RIRB and clear the counter, so a single lost
> response leaves bus->rirb.cmds[addr] non-zero forever.  Each following
> verb then still gets one response that only brings the count back to the
> stale baseline of 1, and snd_hdac_bus_get_response() keeps timing out even
> though the codec answers normally.
> 
> Handle it in the core helper snd_hdac_bus_exec_verb_unlocked(): whenever
> get_response() reports an error, reset the pending counter for the codec
> address, so a late response is simply treated as a spurious response and
> the following verbs recover.  Doing it here covers all HD-audio
> controllers instead of relying on each controller's fallback setting.
> 
> Add a small helper snd_hdac_bus_reset_response_counter() for this.
> 
> Signed-off-by: Bob Song <songxiebing@kylinos.cn>

Applied now to for-next branch.  Thanks.


Takashi