lkml.org 
[lkml]   [2019]   [Jun]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [alsa-devel] [PATCH v2] soundwire: stream: fix bad unlock balance
From
Date


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"?
Yes.
Vinod can update comment while applying this patch?
If not I can respin with correct log.

thanks,
srini

>
> Thanks!
>
>>
>>   =====================================
>>   WARNING: bad unlock balance detected!
>>   5.1.0-16506-gc1c383a6f0a2-dirty #1523 Tainted: G        W
>>   -------------------------------------
>>   aplay/2954 is trying to release lock (&bus->msg_lock) at:
>>   do_bank_switch+0x21c/0x480
>>   but there are no more locks to release!
>>
>> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
>> ---
>>   drivers/soundwire/stream.c | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/soundwire/stream.c b/drivers/soundwire/stream.c
>> index ce9cb7fa4724..73c52cd4fec8 100644
>> --- a/drivers/soundwire/stream.c
>> +++ b/drivers/soundwire/stream.c
>> @@ -814,7 +814,8 @@ static int do_bank_switch(struct
>> sdw_stream_runtime *stream)
>>               goto error;
>>           }
>> -        mutex_unlock(&bus->msg_lock);
>> +        if (bus->multi_link)
>> +            mutex_unlock(&bus->msg_lock);
>>       }
>>       return ret;
>>
>

\
 
 \ /
  Last update: 2019-06-06 16:59    [W:0.058 / U:1.112 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site