#32 /sys/.../BAT0/current_now : no such file

[niko2gare]

hi,

on my laptop (T60 / IBM thinkpad) and a gentoo-sources kernel 2.6.37, it seems that the file current_now is replaced by power_now.
i made a test :
--- #define CURRENT_NOW "current_now"
+++ #define CURRENT_NOW "power_now"

and now works good.

i'm not competent to bring you an enhanced patch, sorry.

if you want more information, let me now.

by

[niko2gare]

the cpufreqd version is 2.4.2

[Mattia Dongili]

thanks for submitting the issue, The fix should at least be backward compatible with earlier versions not having power_now.
Anyway this will be fixed in the next version of cpufreqd.

[niko2gare]

hi,
it seems current_now was removed since 2.6.36, so what do you think about this :

#include <linux/version.h>
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,36)
#define CURRENT_NOW "power_now"
#else
#define CURRENT_NOW "current_now"
#endif

it keeps the CURRENT_NOW name but, in the other hand, it does not change many things...

[niko2gare]

in patch form :

--- cpufreqd_acpi_battery.c 2011-02-08 15:29:24.000000000 +0100
+++ cpufreqd_acpi_battery.c 2011-02-08 15:30:34.000000000 +0100
@@ -22,6 +22,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
+#include <linux/version.h>
#include "cpufreqd_plugin.h"
#include "cpufreqd_acpi.h"
#include "cpufreqd_acpi_event.h"
@@ -35,7 +36,11 @@
#define CHARGE_NOW "charge_now"
#define PRESENT "present"
#define STATUS "status"
-#define CURRENT_NOW "current_now"
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,36)
+#define CURRENT_NOW "power_now"
+#else
+#define CURRENT_NOW "current_now"
+#endif

struct battery_info {
int capacity;

[Mattia Dongili]

No sorry. cpufreqd needs to be able to detect the file at runtime, not compile time. See how it was done for for current_now/energy_now here around line 135:
http://git.kamineko.org/cgi-bin/gitweb.cgi?p=cpufreqd.git;a=blob;f=src/cpufreqd_acpi_battery.c;h=e2da1722e6c1a50d8176d38d153bfab0764c9d54;hb=HEAD

[niko2gare]

you right, i only thought about my gentoo, sorry.

patch hopping current_now is the best way :
--- cpufreqd_acpi_battery.c.orig 2011-02-09 13:17:32.000000000 +0100
+++ cpufreqd_acpi_battery.c 2011-02-09 13:28:32.000000000 +0100
@@ -36,6 +36,7 @@
#define PRESENT "present"
#define STATUS "status"
#define CURRENT_NOW "current_now"
+#define POWER_NOW "power_now"

struct battery_info {
int capacity;
@@ -146,8 +147,12 @@
if (!binfo->status)
return -1;
binfo->current_now = get_class_device_attribute(binfo->cdev, CURRENT_NOW);
- if (!binfo->current_now)
- return -1;
+ if (!binfo->current_now) {
+ /* try the "power_now" name */
+ binfo->current_now = get_class_device_attribute(binfo->cdev, POWER_NOW);
+ if (!binfo->current_now)
+ return -1;
+ }

/* read the last full capacity, this is not going to change
* very often, so no need to poke it later */

or patch knowing that power_now will be the future :
--- cpufreqd_acpi_battery.c.orig 2011-02-09 13:17:32.000000000 +0100
+++ cpufreqd_acpi_battery.c 2011-02-09 13:33:47.000000000 +0100
@@ -36,6 +36,7 @@
#define PRESENT "present"
#define STATUS "status"
#define CURRENT_NOW "current_now"
+#define POWER_NOW "power_now"

struct battery_info {
int capacity;
@@ -145,9 +146,13 @@
binfo->status = get_class_device_attribute(binfo->cdev, STATUS);
if (!binfo->status)
return -1;
- binfo->current_now = get_class_device_attribute(binfo->cdev, CURRENT_NOW);
- if (!binfo->current_now)
- return -1;
+ binfo->current_now = get_class_device_attribute(binfo->cdev, POWER_NOW);
+ if (!binfo->current_now) {
+ /* try the "current_now" name */
+ binfo->current_now = get_class_device_attribute(binfo->cdev, CURRENT_NOW);
+ if (!binfo->current_now)
+ return -1;
+ }

/* read the last full capacity, this is not going to change
* very often, so no need to poke it later */

[niko2gare]

it was allready done with name changing : http://bugs.gentoo.org/show_bug.cgi?id=346399