Re: [alsa-devel] [PATCH v2] soundwire: stream: fix bad unlock balance

From: Pierre-Louis Bossart
Date: Thu Jun 06 2019 - 11:40:10 EST

On 6/6/19 9:58 AM, Srinivas Kandagatla wrote:

On 06/06/2019 15:28, Pierre-Louis Bossart wrote:
On 6/6/19 6:22 AM, Srinivas Kandagatla wrote:
multi bank switching code takes lock on condition but releases without
any check resulting in below warning.
This patch fixes this.

Question to make sure we are talking about the same thing: multi-link bank switching is a capability beyond the scope of the SoundWire spec which requires hardware support to synchronize links and as Sanyog hinted at in a previous email follow a different flow for bank switches.

You would not use the multi-link mode if you have different links that can operate independently and have no synchronization requirement. You would conversely use the multi-link mode if you have two devices on the same type on different links and want audio to be rendered at the same time.

Can you clarify if indeed you were using the full-blown multi-link mode with hardware synchronization or a regular single-link operation? I am not asking for details of your test hardware, just trying to reconstruct the program flow leading to this problem.

Am testing on a regular single link, which hits this path.

It could also be that your commit message was meant to say:
"the msg lock is taken for multi-link cases only but released unconditionally, leading to an unlock balance warning for single-link usages"?

Thanks for the precision. the change is legit so assuming the commit message is reworded to mention single link usage please feel free to take the following tag.

Acked-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>