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

[John Linn]

In reviewing the data sheet for the device, I don't see any shared
information between the 2 channels of the device.

The mutex looks like it's not needed to me also.  

I'll review with some others here to make sure I'm not overlooking
something. 

-- John

> -----Original Message-----
> From: Grant Likely [mailto:glikely at secretlab.ca] On Behalf Of Grant
Likely
> Sent: Thursday, July 03, 2008 11:42 AM
> To: Dmitry Torokhov
> Cc: John Linn; linuxppc-dev at ozlabs.org; linux-input at vger.kernel.org;
jwboyer at linux.vnet.ibm.com;
> jacmet at sunsite.dk; Sadanand Mutyala
> Subject: Re: [PATCH] [V2] powerpc: Xilinx: PS2: Added new XPS PS2
driver
> 
> On Thu, Jul 03, 2008 at 01:27:00PM -0400, Dmitry Torokhov wrote:
> > 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).
> 
> John, correct me if I'm wrong, but I don't think there are any shared
> resources being accessed here and I believe the mutex is entirely
> unnecessary.
> 
> Cheers,
> g.


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