Re: [RFC][PATCH] alarmtimers: Handle late rtc module loading

From: Meelis Roos
Date: Mon Jun 20 2011 - 16:10:16 EST

> > One the PC, I get the following about RTC in dmesg:
> >
> > [ 0.319145] drivers/rtc/hctosys.c: unable to open rtc device (rtc0)
> > [ 3.614132] rtc_cmos 00:03: RTC can wake from S4
> > [ 3.614480] rtc_cmos 00:03: rtc core: registered rtc_cmos as rtc0
> > [ 3.614582] rtc0: alarms up to one year, y3k, 114 bytes nvram
> I'll double check, but I suspect that "unable to open rtc device"
> message isn't new. The issue is that the rtc_cmos driver is built as a
> module, and the hctosys functionality is running before the module is
> loaded.

Yes. But I consider this a configuration error - to load modular rtc
driver and expect boottime clock setting from it works. It was by
mistake - the boottime options came later in time. Changed it to
statically compiled in PC CMOS RTC and it works fine.

> Hmmm. This maybe points to the need for some sort of callback system for
> when RTC devices are registered. Since most existing code is just hoping
> its available by late_init.

Is it really necessary?

Meelis Roos (mroos@xxxxxxxx)
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