Re: linux-next 2017-08-08 keyboard failure on Nokia N900

From: Grygorii Strashko
Date: Tue Aug 08 2017 - 16:17:40 EST




On 08/08/2017 03:09 PM, Julia Lawall wrote:


On Tue, 8 Aug 2017, Grygorii Strashko wrote:



On 08/08/2017 06:12 AM, Pavel Machek wrote:
Hi!

I tried today's linux-next. It boots on n900 (up to X), but then my
screen locks and I can't get back. Touchscreen worked, so my guess is
keyboard does not...? Ssh connection over usb still works.

Confirmed, its the keyboard.

Additionally, battery monitoring fails, because neither

/sys/class/power_supply/{n900-,rx51-}battery/voltage_now

exists.

And dmesg is helpful in this case:

[ 0.675201] input: twl4030_pwrbutton as
/devices/platform/68000000.ocp/48070000.i2c/i2c-1/1-0048/48070000.i2c:twl@48:pwrbutton/input/input1
[ 0.676635] input: TWL4030 Keypad as
/devices/platform/68000000.ocp/48070000.i2c/i2c-1/1-0048/48070000.i2c:twl@48:keypad/input/input2
[ 0.679138] twl4030_keypad 48070000.i2c:twl@48:keypad: request_irq
failed for irq no=156: -13
[ 0.679779] twl4030_keypad: probe of 48070000.i2c:twl@48:keypad
failed with error -13
[ 0.682769] twl4030_madc 48070000.i2c:twl@48:madc: could not
request irq
[ 0.684051] twl4030_madc: probe of 48070000.i2c:twl@48:madc failed
with error -13
[ 0.685852] input: twl4030:vibrator as
/devices/platform/68000000.ocp/48070000.i2c/i2c-1/1-0048/48070000.i2c:twl@48:audio/twl4030-vibra/input/input3
[ 0.768890] omap_i2c 48070000.i2c: bus 1 rev3.3 at 2200 kHz


I've not precisely checked it, but smth is telling me that below
patch can cause this:

commit 78daaca78ee57dead0f4aa5ee399f0499e81cd9e
Author: Julia Lawall <Julia.Lawall@xxxxxxx>
Date: Thu May 4 22:10:50 2017 +0200

mfd: twl4030-irq: Drop unnecessary static

Drop static on a local variable, when the variable is initialized before
any use, on every possible execution path through the function.

--- a/drivers/mfd/twl4030-irq.c
+++ b/drivers/mfd/twl4030-irq.c
@@ -685,7 +685,7 @@ int twl4030_sih_setup(struct device *dev, int module, int irq_base)

int twl4030_init_irq(struct device *dev, int irq_num)
{
- static struct irq_chip twl4030_irq_chip;
+ struct irq_chip twl4030_irq_chip;


but if we will look at code - it can be seen that this variable is passed by reference to
irq_set_chip_and_handler().
Ops. And what will happen when twl4030_init_irq() returns ;)

The patch is not correct as was already noted when it was submitted:

https://lkml.org/lkml/2017/7/15/169
https://lkml.org/lkml/2017/7/15/171

Do you need a patch reverting this one?

Hm. This one is in linux-next, but shouldn't. Right?

git log --oneline -10 linux-next/master
c0b96db Add linux-next specific files for 20170808

git log --oneline linux-next/master | grep "Drop unnecessary static"
78daaca mfd: twl4030-irq: Drop unnecessary static



--
regards,
-grygorii