2006-03-14 08:35:36

by Alexander Gran

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Subject: Re: 2.6.16-rc6-mm1 : Setting clocksource results in error

Hi,

I'm still fiddeling with my way to slow netbeans debugger. I just tried to
change the clocksource. That resulted in an error, but apparently worked. Is
that expected behaviour:
root@t40:/sys/devices/system/clocksource/clocksource0# l
insgesamt 0
-rw------- 1 root root 4,0K 2006-03-14 09:31 available_clocksource
-rw------- 1 root root 0 2006-03-14 09:31 current_clocksource
root@t40:/sys/devices/system/clocksource/clocksource0# cat
available_clocksource
acpi_pm jiffies tsc pit
root@t40:/sys/devices/system/clocksource/clocksource0# echo acpi_pm >
current_clocksource
-su: echo: write error: Das Argument ist ung?ltig
root@t40:/sys/devices/system/clocksource/clocksource0# cat current_clocksource
acpi_pm
root@t40:/sys/devices/system/clocksource/clocksource0# echo tsc >
current_clocksource
-su: echo: write error: Das Argument ist ung?ltig
root@t40:/sys/devices/system/clocksource/clocksource0# cat current_clocksource
tsc
Das Argument ist ung?ltig = Argument is invalid.
dmesg says:
Time: acpi_pm clocksource has been installed.
Time: tsc clocksource has been installed.

regards
Alex

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2006-03-14 19:11:08

by john stultz

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Subject: Re: 2.6.16-rc6-mm1 : Setting clocksource results in error

On Tue, 2006-03-14 at 09:35 +0100, Alexander Gran wrote:
> I'm still fiddeling with my way to slow netbeans debugger. I just tried to
> change the clocksource. That resulted in an error, but apparently worked. Is
> that expected behaviour:
> root@t40:/sys/devices/system/clocksource/clocksource0# l
> insgesamt 0
> -rw------- 1 root root 4,0K 2006-03-14 09:31 available_clocksource
> -rw------- 1 root root 0 2006-03-14 09:31 current_clocksource
> root@t40:/sys/devices/system/clocksource/clocksource0# cat
> available_clocksource
> acpi_pm jiffies tsc pit
> root@t40:/sys/devices/system/clocksource/clocksource0# echo acpi_pm >
> current_clocksource
> -su: echo: write error: Das Argument ist ung?ltig
> root@t40:/sys/devices/system/clocksource/clocksource0# cat current_clocksource
> acpi_pm

Huh. Interesting.

Oh! I see it, we're stripping the \n from the name and returning a count
value one less then what was given.

You can verify it by noticing "echo -n tsc > current_clocksource" does
not give the error.

This small fix should resolve it.

Thanks for the bug report!
-john

Signed-off-by: John Stultz <[email protected]>

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index d2ce2c3..fe22f64 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -220,6 +220,7 @@ sysfs_show_current_clocksources(struct s
static ssize_t sysfs_override_clocksource(struct sys_device *dev,
const char *buf, size_t count)
{
+ size_t ret = count;
/* strings from sysfs write are not 0 terminated! */
if (count >= sizeof(override_name))
return -EINVAL;
@@ -241,7 +242,7 @@ static ssize_t sysfs_override_clocksourc

spin_unlock_irq(&clocksource_lock);

- return count;
+ return ret;
}

/**



2006-03-15 10:53:06

by Alexander Gran

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Subject: Re: 2.6.16-rc6-mm1 : Setting clocksource results in error

Hi,

applied patch. Didn't work?! Same error as before..

regards
Alex


Am Dienstag, 14. M?rz 2006 20:11 schrieb john stultz:
> On Tue, 2006-03-14 at 09:35 +0100, Alexander Gran wrote:
> > I'm still fiddeling with my way to slow netbeans debugger. I just tried
> > to change the clocksource. That resulted in an error, but apparently
> > worked. Is that expected behaviour:
> > root@t40:/sys/devices/system/clocksource/clocksource0# l
> > insgesamt 0
> > -rw------- 1 root root 4,0K 2006-03-14 09:31 available_clocksource
> > -rw------- 1 root root 0 2006-03-14 09:31 current_clocksource
> > root@t40:/sys/devices/system/clocksource/clocksource0# cat
> > available_clocksource
> > acpi_pm jiffies tsc pit
> > root@t40:/sys/devices/system/clocksource/clocksource0# echo acpi_pm >
> > current_clocksource
> > -su: echo: write error: Das Argument ist ung?ltig
> > root@t40:/sys/devices/system/clocksource/clocksource0# cat
> > current_clocksource acpi_pm
>
> Huh. Interesting.
>
> Oh! I see it, we're stripping the \n from the name and returning a count
> value one less then what was given.
>
> You can verify it by noticing "echo -n tsc > current_clocksource" does
> not give the error.
>
> This small fix should resolve it.
>
> Thanks for the bug report!
> -john
>
> Signed-off-by: John Stultz <[email protected]>
>
> diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
> index d2ce2c3..fe22f64 100644
> --- a/kernel/time/clocksource.c
> +++ b/kernel/time/clocksource.c
> @@ -220,6 +220,7 @@ sysfs_show_current_clocksources(struct s
> static ssize_t sysfs_override_clocksource(struct sys_device *dev,
> const char *buf, size_t count)
> {
> + size_t ret = count;
> /* strings from sysfs write are not 0 terminated! */
> if (count >= sizeof(override_name))
> return -EINVAL;
> @@ -241,7 +242,7 @@ static ssize_t sysfs_override_clocksourc
>
> spin_unlock_irq(&clocksource_lock);
>
> - return count;
> + return ret;
> }
>
> /**

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2006-03-15 17:16:22

by john stultz

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Subject: Re: 2.6.16-rc6-mm1 : Setting clocksource results in error

On Wed, 2006-03-15 at 11:53 +0100, Alexander Gran wrote:
> applied patch. Didn't work?! Same error as before..


Huh. Now I'm quite confused. And using the -n option w/ echo doesn't
change the behavior?

thanks
-john



2006-03-15 17:28:39

by Alexander Gran

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Subject: Re: 2.6.16-rc6-mm1 : Setting clocksource results in error

Oh sorry. Lilo got mad my automated kernel-install-script, so I was using the
unpatched kernel again. Works as expected!

Am Mittwoch, 15. M?rz 2006 18:16 schrieb john stultz:
> On Wed, 2006-03-15 at 11:53 +0100, Alexander Gran wrote:
> > applied patch. Didn't work?! Same error as before..
>
> Huh. Now I'm quite confused. And using the -n option w/ echo doesn't
> change the behavior?
>
> thanks
> -john

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2006-03-15 17:32:20

by john stultz

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Subject: Re: 2.6.16-rc6-mm1 : Setting clocksource results in error

On Wed, 2006-03-15 at 18:28 +0100, Alexander Gran wrote:
> Oh sorry. Lilo got mad my automated kernel-install-script, so I was using the
> unpatched kernel again. Works as expected!

Great to hear! Thanks for the testing!
-john