From: Ian Abbott <abbotti@mev.co.uk>
To: Tobias Klauser <klto@zhaw.ch>
Cc: Ian Abbott <ian.abbott@mev.co.uk>,
"sfr@canb.auug.org.au" <sfr@canb.auug.org.au>,
"gregkh@suse.de" <gregkh@suse.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"alan@lxorguk.ukuu.org.uk" <alan@lxorguk.ukuu.org.uk>,
"nios2-dev@sopc.et.ntust.edu.tw" <nios2-dev@sopc.et.ntust.edu.tw>
Subject: Re: [Nios2-dev] [PATCH 2/2] serial: Add driver for the Altera UART
Date: Thu, 6 May 2010 13:47:17 +0100 [thread overview]
Message-ID: <4BE2BA55.6060109@mev.co.uk> (raw)
In-Reply-To: <4BE2B02B.4010209@zhaw.ch>
Hi Tobias,
On 06/05/10 13:03, Tobias Klauser wrote:
> I also noticed, that altera_uart_break_ctl takes the lock which might be
> not necessary as the caller in serial_core.c already takes port->mutex
> which should be enough. Or am I wrong?
It's not enough. The spin lock is needed to protect modification of
pp->imr and writing this modified value to the control register. Not
all paths that modify pp->imr and the control register grab port->mutex
beforehand (for example, the interrupt routine doesn't and can't).
--
-=( Ian Abbott @ MEV Ltd. E-mail: <abbotti@mev.co.uk> )=-
-=( Tel: +44 (0)161 477 1898 FAX: +44 (0)161 718 3587 )=-
prev parent reply other threads:[~2010-05-06 12:47 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-05 8:35 [PATCH v5 0/2] serial: Drivers for Altera UARTs Tobias Klauser
2010-05-05 8:35 ` [PATCH 1/2] serial: Add driver for the Altera JTAG UART Tobias Klauser
2010-05-06 10:59 ` [Nios2-dev] " Ian Abbott
2010-05-06 11:17 ` Alan Cox
2010-05-05 8:35 ` [PATCH 2/2] serial: Add driver for the Altera UART Tobias Klauser
2010-05-06 10:44 ` [Nios2-dev] " Ian Abbott
2010-05-06 11:09 ` Ian Abbott
2010-05-06 11:16 ` Ian Abbott
2010-05-06 12:03 ` Tobias Klauser
2010-05-06 12:47 ` Ian Abbott [this message]
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