2011-02-25 02:41:48

by stuart h

[permalink] [raw]
Subject: [PATCH v2] dcdbas: force SMI to happen when expected


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 <[email protected]>
---

--- 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),




2011-03-01 14:57:56

by Jiri Kosina

[permalink] [raw]
Subject: Re: [PATCH v2] dcdbas: force SMI to happen when expected

On Thu, 24 Feb 2011, stuart h 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 <[email protected]>

As this doesn't seem to be picked up ... Douglas, can I have your
Acked-by: please, so that I could merge it (as Acked by maintainer?).

Thanks.

> --- 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),
>
>
>

--
Jiri Kosina
SUSE Labs, Novell Inc.

2011-03-01 15:54:04

by Doug Warzecha

[permalink] [raw]
Subject: Re: [PATCH v2] dcdbas: force SMI to happen when expected

On 02/24/2011 8:35 PM, Stuart Hayes 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 <[email protected]>
> ---
>
> --- 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 <[email protected]>

2011-03-02 12:42:34

by Jiri Kosina

[permalink] [raw]
Subject: Re: [PATCH v2] dcdbas: force SMI to happen when expected

On Tue, 1 Mar 2011, [email protected] 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 <[email protected]>
> > ---
> >
> > --- 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 <[email protected]>

Applied, thanks.

--
Jiri Kosina
SUSE Labs, Novell Inc.