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From: Takashi Iwai <tiwai@suse.de>
To: Jerome Brunet <jbrunet@baylibre.com>
Cc: Mark Brown <broonie@kernel.org>,
	Liam Girdwood <lgirdwood@gmail.com>,
	alsa-devel@alsa-project.org,
	Russell King <rmk+kernel@armlinux.org.uk>,
	linux-kernel@vger.kernel.org
Subject: Re: [alsa-devel] [PATCH 0/2] ASoC: hdmi-codec: fix locking issue
Date: Wed, 23 Oct 2019 18:23:20 +0200	[thread overview]
Message-ID: <s5ha79rph1j.wl-tiwai@suse.de> (raw)
In-Reply-To: <20191023161203.28955-1-jbrunet@baylibre.com>

On Wed, 23 Oct 2019 18:12:01 +0200,
Jerome Brunet wrote:
> 
> This patchset fixes the locking issue reported by Russell.
> 
> As explained a mutex was used as flag and held while returning to
> userspace.
> 
> Patch 2 is entirely optional and switches from bit atomic operation
> to mutex again. I tend to prefer bit atomic operation in this
> particular case but either way should be fine.

I fail to see why the mutex is needed there.  Could you elaborate
about the background?

IIUC, the protection with the atomic bitmap should guarantee the
exclusive access.  The mutex would allow the possible concurrent calls
of multiple startup of a single instance, but is this the thing to be
solved?


thanks,

Takashi

> 
> Jerome Brunet (2):
>   Revert "ASoC: hdmi-codec: re-introduce mutex locking"
>   ASoC: hdmi-codec: re-introduce mutex locking again
> 
>  sound/soc/codecs/hdmi-codec.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> -- 
> 2.21.0
> 
> _______________________________________________
> Alsa-devel mailing list
> Alsa-devel@alsa-project.org
> https://mailman.alsa-project.org/mailman/listinfo/alsa-devel
> 

  parent reply	other threads:[~2019-10-23 16:23 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-23 16:12 Jerome Brunet
2019-10-23 16:12 ` [PATCH 1/2] Revert "ASoC: hdmi-codec: re-introduce mutex locking" Jerome Brunet
2019-10-23 16:37   ` Mark Brown
2019-10-23 18:26     ` Russell King - ARM Linux admin
2019-10-23 18:46       ` Mark Brown
2019-10-23 18:56   ` Applied "ASoC: hdmi-codec: drop mutex locking again" to the asoc tree Mark Brown
2019-10-23 16:12 ` [PATCH 2/2] ASoC: hdmi-codec: re-introduce mutex locking again Jerome Brunet
2019-10-23 16:23 ` Takashi Iwai [this message]
2019-10-23 17:53   ` [alsa-devel] [PATCH 0/2] ASoC: hdmi-codec: fix locking issue Jerome Brunet
2019-10-24 11:34     ` Mark Brown
2019-10-24 12:15       ` Takashi Iwai

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