On Tue, Jun 19, 2007 at 14:24:04 +0200, Alessandro Zummo wrote: > On Fri, 15 Jun 2007 09:03:19 +0200 > Tino Keitel <[EMAIL PROTECTED]> wrote: > > > > > I have the following strange behaviour with rtc_cmos: > > > > > > > > $ echo 1181934240 > /sys/class/rtc/rtc0/wakealarm > > > > bash: echo: write error: Device or resource busy > > > > $ rmmod rtc_cmos > > > > $ modprobe rtc_cmos > > > > $ echo 1181934240 > /sys/class/rtc/rtc0/wakealarm > > > > $ echo 1181934240 > /sys/class/rtc/rtc0/wakealarm > > > > bash: echo: write error: Device or resource busy > > > > $ > > > > > > If the alarm has already been enabled, you cannot set the next > > > alarm. You should disable first. > > > > Ah, ok. > > > > Where is the documentation that describes that I have to disable it > > first, and how to do this? A migration document for > > /proc/acpi/alarm users would be nice, too. > > Well, I guess there is no documentation. Maybe we could add > a dev_warn with an explicit message.
Isn't it somewhat ridiculous to plan the removal of a feature for several months, and then replace it with something that behaves differently without any documentation? I don't know if there is any centralized form sysfs documentation. I guess not. So at least a short text like the one below somewhere in Documentation/ would be useful. I still wonder how 'cat /sys/class/rtc/rtcX/wakealarm' is expected to behave. With 2.6.22-rc5, I get this: $ echo 1182351177 > /sys/class/rtc/rtc0/wakealarm $ cat /sys/class/rtc/rtc0/wakealarm 2051644873 There seems to be a constant difference of 869984896 seconds. Is this a bug? ----------------------------------------------------------------------- How to use /sys/class/rtc/rtcX/wakealarm ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This file takes the seconds since epoch to enable a wake event at the specified time. If a '0' is written, the alarm is disabled. If the alarm was already enabled, a new alarm can only be set after the old alarm is disabled. Migration from /proc/acpi/alarm ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Users of /proc/acpi/alarm have to change their code to supply the seconds since epoch instead of a date string. For shell scripts, this can be done using the date command, e.g. like this: date -d tomorrow "+%s" This returns the seconds since epoch of the current time on the following day. Please note that you have to disable the old alarm first, if you want to set a new alarm. Otherwise, you get an error. Example: echo 12345 > /sys/class/rtc/rtc0/wakealarm echo 0 > /sys/class/rtc/rtc0/wakealarm echo 23456 > /sys/class/rtc/rtc0/wakealarm ----------------------------------------------------------------------- Regards, Tino - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
