therm_adt746x: -3 invalid for parameter limit_adjust

[Jean Delvare]

Hi Christian,

On Thu, 26 Sep 2013 02:16:16 -0700 (PDT), Christian Kujau wrote:
> Hi,
> 
> after upgrading from 3.11 to 3.12-rc2, the therm_adt746x module could not 
> be loaded any more:
> 
>   therm_adt746x: `-2' invalid for parameter `limit_adjust'
> 
> I've alwasy passed "limit_adjust=-3" (negative 3) to the module via 
> modprobe.conf, to lower the max temperature. Up until 3.11, loading the 
> module would print:
> 
>   adt746x: Lowering max temperatures from 73, 80, 109 to 67, 47, 67
> 
> I can load the module without limit_adjust or with positive values, but 
> really wanted to lower the temperature, so that the fan would kick in 
> earlier. For reference, this is what happens in 3.12-rc2:
> 
>  v--- limit_adjust
>  |
>  0: adt746x: Lowering max temperatures from 73, 80, 109 to 70, 50, 70
>  1: adt746x: Lowering max temperatures from 73, 80, 109 to 71, 51, 71
>  2: adt746x: Lowering max temperatures from 73, 80, 109 to 72, 52, 72
>  3: adt746x: Lowering max temperatures from 73, 80, 109 to 73, 53, 73
>  4: adt746x: Lowering max temperatures from 73, 80, 109 to 74, 54, 74
> 10: adt746x: Lowering max temperatures from 73, 80, 109 to 80, 60, 80
> 
> Was passing negative values to therm_adt746x ever supported?

As far as I can see, yes.

> drivers/macintosh/therm_adt746x.c hasn't been touched in a while, this 
> means some other change did it.
> 
> Before I attempt a full git bisect, any hints what could have caused this?

I think it is a bug in:

commit 6072ddc8520b86adfac6939ca32fb6e6c4de017a
Author: Jingoo Han <jg1.han at samsung.com>
Date:   Thu Sep 12 15:14:07 2013 -0700

    kernel: replace strict_strto*() with kstrto*()

The change was a good idea but the code itself is not, it has kstrtoul
in many places where kstrtol should be used. Please try the following
patch, hopefully that should fix your problem:

From: Jean Delvare <khali at linux-fr.org>
Subject: kernel/params: Fix handling of signed integer types

Commit 6072ddc8520b86adfac6939ca32fb6e6c4de017a broke the handling
of signed integer types, fix it.

Reported-by: Christian Kujau <lists at nerdbynature.de>
Signed-off-by: Jean Delvare <khali at linux-fr.org>
Cc: Jingoo Han <jg1.han at samsung.com>
Cc: Andrew Morton <akpm at linux-foundation.org>
---
 kernel/params.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- linux-3.12-rc2.orig/kernel/params.c	2013-09-24 00:41:09.000000000 +0200
+++ linux-3.12-rc2/kernel/params.c	2013-09-26 11:32:43.434586197 +0200
@@ -254,11 +254,11 @@ int parse_args(const char *doing,
 
 
 STANDARD_PARAM_DEF(byte, unsigned char, "%hhu", unsigned long, kstrtoul);
-STANDARD_PARAM_DEF(short, short, "%hi", long, kstrtoul);
+STANDARD_PARAM_DEF(short, short, "%hi", long, kstrtol);
 STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, kstrtoul);
-STANDARD_PARAM_DEF(int, int, "%i", long, kstrtoul);
+STANDARD_PARAM_DEF(int, int, "%i", long, kstrtol);
 STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, kstrtoul);
-STANDARD_PARAM_DEF(long, long, "%li", long, kstrtoul);
+STANDARD_PARAM_DEF(long, long, "%li", long, kstrtol);
 STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, kstrtoul);
 
 int param_set_charp(const char *val, const struct kernel_param *kp)


-- 
Jean Delvare