[alsa-devel] [PATCH 0/1] ALSA: hda: add fallback to polling to hdac_bus_get_response()

[Kai Vehmanen]

Hi,

On Mon, 7 Oct 2019, Takashi Iwai wrote:

> > I found a discrepancy in behaviour between snd-hda-intel and SOF, despite
> > using the same snd-hda-codec-hdmi as the codec driver.
[...]
> 
> While it's OK to add the polling support in the core code, I suspect
> that the main problem gets solved by setting the write_sync flag as
> the commit 2756d9143aa5.  For SOF/SST, you may set the flag
> unconditionally since they support only the new chipsets.

I've been meaning to try that out, and indeed, if I set write-sync 
on SOF side, it helps in this specific ICL case as well. I'll push a patch 
via Pierre's SOF tree:
 https://github.com/thesofproject/linux/pull/1281 

... this makes the polling fallback patch less urgent, but probably better 
to apply that as well, just to align behaviour between different HDAC 
users.

I'll also check whether we could remove the older workaround for CFL and 
CNL that force polling mode on these platforms. It is highly likely these 
workarounds are no longer needed with sync-write set.

> I've been traveling (still for the next week), so the further reply
> may be delayed.

Ack, thanks. I'll do some more testing around these flows during 
the week.

Br, Kai