Re: [PATCH] [V2] powerpc: Xilinx: PS2: Added new XPS PS2 driver

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

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