linux-kernel - i8042 error at booting an Intel Cherry Trail-based device

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Date:   Mon, 28 Nov 2016 14:56:36 +0100
From:   Takashi Iwai <tiwai@...e.de>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:     linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: i8042 error at booting an Intel Cherry Trail-based device

Hi Dmitry,

I've been testing a small machine with Intel Cherry Trail chipset, and
noticed that the kernel spews errors always like:

 i8042: PNP: No PS/2 controller found. Probing ports directly.
 i8042: Can't read CTR while initializing i8042
 i8042: probe of i8042 failed with error -5

Especially the second one ("Can't read CTR...") is annoying since it's
in KERN_ERR level and thus appears even booted with quiet boot
option.  Actually this is the only error message appearing at boot, so
I'd love to get rid of it.

What is the preferred way to reduce this?  For example, is a patch
like below OK to simply change the log level and the error code?

thanks,

Takashi

-- 8< --
From: Takashi Iwai <tiwai@...e.de>
Subject: [PATCH] i8042: Reduce the log level of i8042 CTR read error

The error message "Can't read CTR while initializing i8042" appears on
Cherry Trail-based devices at each boot time:

  i8042: PNP: No PS/2 controller found. Probing ports directly.
  i8042: Can't read CTR while initializing i8042
  i8042: probe of i8042 failed with error -5

This is annoying, since it's the only error message with KERN_ERR
level appearing during the boot.

This patch changes the kernel log level to KERN_INFO for that message,
and replaces the error code to -ENODEV so that this probe failure
won't be complained like the above.

Signed-off-by: Takashi Iwai <tiwai@...e.de>
---
 drivers/input/serio/i8042.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
index b4e1ac5c9ea8..2c2683e357e9 100644
--- a/drivers/input/serio/i8042.c
+++ b/drivers/input/serio/i8042.c
@@ -980,8 +980,8 @@ static int i8042_controller_init(void)
 			udelay(50);

 		if (i8042_command(&ctr[n++ % 2], I8042_CMD_CTL_RCTR)) {
-			pr_err("Can't read CTR while initializing i8042\n");
-			return -EIO;
+			pr_info("Can't read CTR while initializing i8042\n");
+			return -ENODEV;
 		}

 	} while (n < 2 || ctr[0] != ctr[1]);
-- 
2.10.2