linux-kernel - Re: [PATCH v2] dcdbas: force SMI to happen when expected

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Message-ID: <alpine.LRH.2.00.1103021342170.25727@twin.jikos.cz>
Date:	Wed, 2 Mar 2011 13:42:26 +0100 (CET)
From:	Jiri Kosina <jkosina@...e.cz>
To:	Douglas_Warzecha@...l.com
Cc:	stuart_hayes@...oo.com, linux-kernel@...r.kernel.org,
	Shyam_Iyer@...l.com
Subject: Re: [PATCH v2] dcdbas: force SMI to happen when expected

On Tue, 1 Mar 2011, Douglas_Warzecha@...l.com wrote:

> > This is a reworked version of a very similar patch I sent about three
> > weeks ago... a flaw was pointed out with the original.  That patch
> > didn't make it into the kernel, though, so I'm just sending this one as
> > a new patch.
> > 
> > The dcdbas driver can do an I/O write to cause a SMI to occur.  The SMI
> > handler looks at certain registers and memory locations, so the SMI
> > needs to happen immediately.  On some systems I/O writes are posted,
> > though, causing the SMI to happen well after the "outb" occurred, which
> > causes random failures.  Following the "outb" with an "inb" forces the
> > write to go through even if it is posted.
> > 
> > This patch is against the 2.6.37.1 kernel.
> > 
> > Signed-off-by: Stuart Hayes <stuart_hayes@...oo.com>
> > ---
> > 
> > --- linux-2.6.37/drivers/firmware/dcdbas.c	2011-01-18
> > 10:44:44.869882461 -0500
> > +++ linux-2.6.37_test/drivers/firmware/dcdbas.c	2011-02-24
> > 13:23:58.663771596 -0500
> > @@ -268,8 +268,10 @@ int dcdbas_smi_request(struct smi_cmd *s
> >  	}
> > 
> >  	/* generate SMI */
> > +	/* inb to force posted write through and make SMI happen now */
> >  	asm volatile (
> > -		"outb %b0,%w1"
> > +		"outb %b0,%w1\n"
> > +		"inb %w1"
> >  		: /* no output args */
> >  		: "a" (smi_cmd->command_code),
> >  		  "d" (smi_cmd->command_address),
> > 
> 
> Acked-by: Doug Warzecha <douglas_warzecha@...l.com>

Applied, thanks.

-- 
Jiri Kosina
SUSE Labs, Novell Inc.

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