On Mon, Jul 21, 2008 at 09:04:13PM -0600, Michal Hocko wrote:
> [fixing bad linux kernel mailing list email address - sorry, but gmail's
> thrown mailing delivery error to the spam]
>
> On Tue, Jul 22, 2008 at 01:03:11AM +0400, Alexey Starikovskiy wrote:
> > Hi Michal,
>
> Hi Alexey,
>
> >
> > the charge_now part of your patch seems to be correct, but the
> > calculation is somehow broken --
>
> I have made some experiments and the result is quite surprising to me.
> It seems that this problem is somehow related to Debian distribution
> kernel, because I wasn't able to reproduce it with the Vanilla kernel (I
> had to screw something up last time when I have checked that and
> reported in the original message).
>
> I have tried 3 configurations:
> * 2.6.25 - Vanilla kernel with config-2.6.25 config and result output in
> powertop-2.6.25-good
> * 2.6.25-2 - Debian distribution kernel with config-2.6.25-2 config and
> powertop-2.6.25-2-bad output
> * 2.6.26 - Vanilla kernel with config-2.6.26 config and result output in
> powertop-2.6.26-good
[...]
I had some time to get back to this issue and the problem why I have
seen different behavior on distribution and vanilla kernel was in
configuration.
While distribution kernel doesn't use CONFIG_ACPI_PROCFS_POWER=y while
my vanilla kernel configuration does! This means that the patched code
wasn't triggered in my vanilla kernel testing.
So that I have checked the print_batter_sysfs again and it seems that
the problem is on another place:
powertop.c:648
sprintf(filename, "/sys/class/power_supply/%s/current_now",
dirent->d_name);
file = fopen(filename, "r");
if (!file)
continue;
memset(line, 0, 1024);
if (fgets(line, 1024, file) != NULL) {
watts_drawn = strtoull(line, NULL, 10) / 1000000.0;
}
fclose(file);
if (!dontcount) {
rate += watts_drawn + voltage * amperes_drawn;
}
current rate (later used for the remaining time calculation:
display.c:201
sprintf(buffer, _("Power usage (ACPI estimate): %3.1fW (%3.1f hours)"),
rate, cap/rate);
)
is calculated as watts_drawn + voltage which is not correct, because
current_* values are in A and not in W (according to
linux-src/Documentation/power/power_supply_class.txt).
Updated patch is attached. This one is already working for me.
--
Michal Hocko
From: [EMAIL PROTECTED]
Subject: [PATCH] use charge_now when energy_now is not present
Some batteries (like one in the Futjitsu Siemens Lifebook S71110) don't
export energy_now attribute and exports only change_now in the power_supply
sys directory.
However, we can use this value when it is multiplied by current voltage.
In addition, /sys/class/power_supply/*/current_* are in ľA according to the
linux-src/Documentation/power/power_supply_class.txt and not in ľW as
expected by the original code
Signed-off-by: Michal Hocko <[EMAIL PROTECTED]>
Index: powertop/powertop.c
===================================================================
--- powertop.orig/powertop.c 2008-09-01 14:19:21.000000000 -0600
+++ powertop/powertop.c 2008-09-01 14:27:07.000000000 -0600
@@ -630,12 +630,19 @@ void print_battery_sysfs(void)
sprintf(filename, "/sys/class/power_supply/%s/energy_now", dirent->d_name);
file = fopen(filename, "r");
- if (!file)
- continue;
- memset(line, 0, 1024);
- if (fgets(line, 1024, file) != NULL) {
- watts_left = strtoull(line, NULL, 10) / 1000000.0;
+ watts_left = 1;
+ if (!file) {
+ sprintf(filename, "/sys/class/power_supply/%s/charge_now", dirent->d_name);
+ file = fopen(filename, "r");
+ if (!file)
+ continue;
+
+ /* W = A * V */
+ watts_left = voltage;
}
+ memset(line, 0, 1024);
+ if (fgets(line, 1024, file) != NULL)
+ watts_left *= strtoull(line, NULL, 10) / 1000000.0;
fclose(file);
sprintf(filename, "/sys/class/power_supply/%s/current_now", dirent->d_name);
@@ -644,7 +651,7 @@ void print_battery_sysfs(void)
continue;
memset(line, 0, 1024);
if (fgets(line, 1024, file) != NULL) {
- watts_drawn = strtoull(line, NULL, 10) / 1000000.0;
+ amperes_drawn = strtoull(line, NULL, 10) / 1000000.0;
}
fclose(file);
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