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Date: Thu, 3 Jul 2008 13:27:00 -0400
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: John Linn <john.linn@xilinx.com>
Subject: Re: [PATCH] [V2] powerpc: Xilinx: PS2: Added new XPS PS2 driver
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Cc: Sadanand <sadanan@xilinx.com>, linuxppc-dev@ozlabs.org,
	linux-input@vger.kernel.org
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Hi John,

On Thu, Jul 03, 2008 at 09:42:31AM -0700, John Linn wrote:
> +
> +	/* Initialize the PS/2 interface */
> +	mutex_lock(&drvdata->cfg_mutex);
> +	if (xps2_initialize(drvdata)) {
> +		mutex_unlock(&drvdata->cfg_mutex);
> +		dev_err(dev, "Could not initialize device\n");
> +		retval = -ENODEV;
> +		goto failed3;
> +	}
> +	mutex_unlock(&drvdata->cfg_mutex);

The drvdata is allocated per-port and so both (there are 2 PS/2 ports,
right?) ports get their own copy of cfg_mutex. Since you are trying to
serialze access to resource shared by both ports it will not work.
The original driver-global mutex was appropriate (the only thing I
objected there was use of a counting semaphore instead of a mutex).

-- 
Dmitry