linux-kernel - Re: [1/4] gpio: gpio-f7188x: Use mutex for access serialisation.

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Message-ID: <20150912152643.4e5bb384@x2>
Date:	Sat, 12 Sep 2015 15:26:43 +0200
From:	Vincent Pelletier <plr.vincent@...il.com>
To:	Simon Guinot <simon.guinot@...uanux.org>
Cc:	linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
	Vincent Donnefort <vdonnefort@...il.com>,
	Yoann Sculo <yoann@...lo.fr>
Subject: Re: [1/4] gpio: gpio-f7188x: Use mutex for access serialisation.

Hello Simon,

On Thu, 10 Sep 2015 00:01:40 +0200, Simon Guinot
<simon.guinot@...uanux.org> wrote:
> Vincent (Donnefort) finally succeeds to reproduce the issue. The setup
> is quite simple. You only have to flood the gpio-f7188x driver via the
> sysfs GPIO interface. Nothing more is needed.
> 
> After some debugging we discovered that the problem comes from the
> __request_region function which don't handle very well concurrent
> requests on a muxed region.
> 
> I will send a patch as a reply to this email. Please, can you test it ?

I reverted my mutex-adding commit, applied given patch, and could not
reproduce the error after a few minutes with my test-case, so I think
this solves the issue.

Tested-by: Vincent Pelletier <plr.vincent@...il.com>


I rebased my others gpio patches, unrelated to this issue:

gpio: gpio-f7188x: Implement get_direction.
gpio: gpio-f7188x: "get" should retrieve sensed level when available.
gpio: gpio-f7188x: GPIO bank 0 bit 0 is not available on f71869a

Should I resend ?
I have not checked other model's datasheets, FWIW.

Regards,
-- 
Vincent Pelletier
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