linux-kernel - Re: [BUG 2.6.20-rc2] atkbd.c: Spurious ACK

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Date:	Fri, 29 Dec 2006 20:08:15 +0100
From:	Rene Herman <rene.herman@...il.com>
To:	Dmitry Torokhov <dtor@...ightbb.com>
CC:	Laurent Riffard <laurent.riffard@...e.fr>,
	Dave Jones <davej@...hat.com>,
	Linux Kernel <linux-kernel@...r.kernel.org>,
	Vojtech Pavlik <vojtech@...e.cz>
Subject: Re: [BUG 2.6.20-rc2] atkbd.c: Spurious ACK

Laurent Riffard wrote:

> Le 29.12.2006 06:54, Rene Herman a écrit :

>> Not even an analog camera, but with or without the above, I get a single:
>>
>> " <7>drivers/input/serio/i8042.c: fa <- i8042 (interrupt, 0, 1) [ 902]"

... and when I add "debug" as a kernel param so that I actually get to 
see them (doh) I get the same as Laurent:

> ====
> drivers/input/serio/i8042.c: fa <- i8042 (interrupt, 0, 1) [35172]
> drivers/input/serio/i8042.c: fa <- i8042 (interrupt, 0, 1) [35172]
> atkbd.c: Spurious ACK on isa0060/serio0. Some program might be trying 
> access hardware directly.
> drivers/input/serio/i8042.c: fa <- i8042 (interrupt, 0, 1) [35296]
> drivers/input/serio/i8042.c: fa <- i8042 (interrupt, 0, 1) [35297]
> atkbd.c: Spurious ACK on isa0060/serio0. Some program might be trying 
> access hardware directly.
> drivers/input/serio/i8042.c: fa <- i8042 (interrupt, 0, 1) [35420]
> drivers/input/serio/i8042.c: fa <- i8042 (interrupt, 0, 1) [35421]
> atkbd.c: Spurious ACK on isa0060/serio0. Some program might be trying 
> access hardware directly.
> drivers/input/serio/i8042.c: fa <- i8042 (interrupt, 0, 1) [35544]
> drivers/input/serio/i8042.c: fa <- i8042 (interrupt, 0, 1) [35545]
> atkbd.c: Spurious ACK on isa0060/serio0. Some program might be trying 
> access hardware directly.
> ===

I tried just ignoring more ACKs in i8042_interrupt() but that didn't do 
anything other than alternating between 2 and 1 i8042.c printks between 
atkbd.c printks when ignoring an even or oneven number, respectively. I 
guess it's atkbd.c which needs to ack something to keep it from just 
being delivered over and over again or something like it?

If I apply the following, things seem to be working for me; no "Spurious 
ACK" messages anymore (but a steady stream of fa's from i8042). Not a 
real fix, but I hope it's enough of a clue for someone who understands 
the infrastructure here. Vojtech added to CC as well.

I by the way also tried plugging in a PS/2 mouse (I normally use a USB 
mouse), adding atkbd_reset=1 to the kernel params and lifting the

        if (!flags && data == ATKBD_RET_ACK)
                 atkbd->resend = 0;

out of the ! __i386__ define. No help.

diff --git a/drivers/input/keyboard/atkbd.c b/drivers/input/keyboard/atkbd.c
index c621a91..5f88dde 100644
--- a/drivers/input/keyboard/atkbd.c
+++ b/drivers/input/keyboard/atkbd.c
@@ -372,9 +372,8 @@ #if !defined(__i386__) && !defined (__x8
  		atkbd->resend = 0;
  #endif

-	if (unlikely(atkbd->ps2dev.flags & PS2_FLAG_ACK))
-		if  (ps2_handle_ack(&atkbd->ps2dev, data))
-			goto out;
+	if (ps2_handle_ack(&atkbd->ps2dev, data))
+		goto out;

  	if (unlikely(atkbd->ps2dev.flags & PS2_FLAG_CMD))
  		if  (ps2_handle_response(&atkbd->ps2dev, data))

Rene.

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