linux-kernel - RE: [PATCH] Input: i8042-io - Exclude mips platforms when allocating/deallocating IO regions.

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Message-ID: <E2EE47005FA75F44B80E1019FDD2EBBB6E38B06D@BADAG02.ba.imgtec.org>
Date:	Mon, 27 Jan 2014 00:32:36 +0000
From:	Raghu Gandham <Raghu.Gandham@...tec.com>
To:	Dmitry Torokhov <dmitry.torokhov@...il.com>
CC:	"aaro.koskinen@....fi" <aaro.koskinen@....fi>,
	"linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
	"linux-mips@...ux-mips.org" <linux-mips@...ux-mips.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH] Input: i8042-io - Exclude mips platforms when
 allocating/deallocating IO regions.

Hi Dmitry, 

> 
> On Sat, Jan 25, 2014 at 11:01:54AM -0800, Raghu Gandham wrote:
> > The standard IO regions are already reserved by the platform code on
> > most MIPS devices(malta, cobalt, sni). The Commit
> > 197a1e96c8be5b6005145af3a4c0e45e2d651444
> > ("Input: i8042-io - fix up region handling on MIPS") introduced a bug
> > on these MIPS platforms causing i8042 driver to fail when trying to reserve
> IO ports.
> > Prior to the above mentioned commit request_region is skipped on MIPS
> > but release_region is called.
> >
> > This patch reverts commit 197a1e96c8be5b6005145af3a4c0e45e2d651444
> and
> > also avoids calling release_region for MIPS.
> 
> The problem is that IO regions are reserved on _most_, but not _all_ devices.
> MIPS should figure out what they want to do with i8042 registers and be
> consistent on all devices.

Please examine the attached patch which went upstream in April of 2004.  Since then
it had been a convention not to call request_region routine in i8042 for MIPS. The
attached patch had a glitch that it guarded request_region in i8042-io.h but skipped 
guarding release_region in i8042-io.h. I believe that the issue Aaro saw was due to this 
glitch. Below is the error quoted in Aaro's commit message.

    [    2.112000] Trying to free nonexistent resource <0000000000000060-000000000000006f>

My patch reinstates the convention followed on MIPS devices along with fixing Aaro's issue.

Thanks,
Raghu

View attachment "patch.txt" of type "text/plain" (10823 bytes)