linux-kernel - Re: [PATCH v3] ASoC: AMD: Fix race condition between register access

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Message-ID: <9b80c3da-c137-f1a3-fd50-85ecb9e3f6a4@amd.com>
Date:   Wed, 19 Dec 2018 10:45:27 +0000
From:   "Agrawal, Akshu" <Akshu.Agrawal@....com>
To:     Mark Brown <broonie@...nel.org>
CC:     "djkurtz@...omium.org" <djkurtz@...omium.org>,
        "Deucher, Alexander" <Alexander.Deucher@....com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>,
        "Mukunda, Vijendar" <Vijendar.Mukunda@....com>,
        Guenter Roeck <linux@...ck-us.net>,
        "moderated list:SOUND - SOC LAYER / DYNAMIC AUDIO POWER MANAGEM..." 
        <alsa-devel@...a-project.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3] ASoC: AMD: Fix race condition between register access



On 11/5/2018 4:45 PM, Mark Brown wrote:
> On Wed, Oct 31, 2018 at 09:24:10PM +0000, Agrawal, Akshu wrote:
> 
>> +/* Lock to protect access to registers */
>> +static DEFINE_SPINLOCK(lock);
>> +
> 
> Why is this a global variable and not a part of the driver structure?
> Is there some interaction between multiple instances?
>
Yes, this lock is used to protect registers which are common to multiple
instances and can cause issue in cases such as simultaneous playback and
capture.

Thanks,
Akshu