Re: v4.10-rc4 to v4.10-rc5: battery regression on Nokia N900

From: Guenter Roeck
Date: Tue Jan 24 2017 - 09:18:43 EST

On 01/23/2017 11:37 PM, Pavel Machek wrote:
On Tue 2017-01-24 15:06:39, Zhang Rui wrote:
On Mon, Jan 23, 2017 at 03:49:12PM -0800, Guenter Roeck wrote:
On Tue, Jan 24, 2017 at 12:26:54AM +0100, Pavel Machek wrote:

I'll try to revert it on the top of v4.10-rc5 now... and yes, it fixes
the issue.

Any idea what went wrong and how to fix that?

Anyway as we are at -rc5 and this is warning fix that caused a
regression on different hardware... it should be reverted.


What exactly does "stopped working" mean ? That might help understanding
what went wrong.

/sys files related to battery no longer appear. I beieve this has
something to do with it:

[ 2.374877] of_get_named_gpiod_flags: parsed 'reset-gpios' property
of node '/ocp@68000000/spi@48098000/tsc2005@0[0]' - status (0)
[ 2.375946] input: TSC2005 touchscreen as
[ 2.392120] rx51-battery: probe of n900-battery failed with error

Mystery solved:

diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
index 3932f92..fe5ec82 100644
--- a/drivers/hwmon/hwmon.c
+++ b/drivers/hwmon/hwmon.c
@@ -545,8 +545,10 @@ __hwmon_device_register(struct device *dev, const char *name, void *drvdata,
int i, j, err, id;

/* Do not accept invalid characters in hwmon name attribute */
- if (name && (!strlen(name) || strpbrk(name, "-* \t\n")))
+ if (name && (!strlen(name) || strpbrk(name, "-* \t\n"))) {
+ printk("hwmon: Invalid character detected: %s\n", name);
return ERR_PTR(-EINVAL);
+ }

id = ida_simple_get(&hwmon_ida, 0, 0, GFP_KERNEL);
if (id < 0)

pavel@n900:~$ dmesg | grep -5 Invalid
[ 0.829650] of_get_named_gpiod_flags: parsed 'gpio-reset' property
of node '/ocp@68000000/i2c@48072000/tlv320aic3x@19[0]' - status (0)
[ 0.833831] tsl2563 2-0029: model 7, rev. 0
[ 0.837768] of_get_named_gpiod_flags: parsed 'enable-gpio' property
of node '/ocp@68000000/i2c@48072000/lp5523@32[0]' - status (0)
[ 1.921417] omap_i2c 48072000.i2c: controller timed out
[ 2.056823] lp5523x 2-0032: lp5523 Programmable led chip found
[ 2.064147] hwmon: Invalid character detected: bq27200-0

So the problem is really that the thermal driver needs to create a valid name.


Before reverting, can you please try if this patch works or not?

Not really. Revert now. Sorry.

Are you sure? This does not look equivalent to me at all.

"name" file handling moved from drivers to the core, which added some
crazy checks what name can contain. Even if this "works", what is the
expected effect on the "name" file?

The hwmon name attribute must not include '-', as documented in
Documentation/hwmon/sysfs-interface. Is enforcing that 'crazy' ?
Maybe in your world, but not in mine.