Re: [RFC] Option to disable mapping genrtc calls to ppc_md calls

[Tom Rini <trini@kernel.crashing.org>]

On Tue, Jan 18, 2005 at 11:25:33AM -0500, Dan Malek wrote:
> 
> On Jan 18, 2005, at 11:15 AM, Tom Rini wrote:
> 
> >On Mon, Jan 17, 2005 at 02:10:00PM -0700, Mark A. Greer wrote:
> 
> >>There are 2 reasons to not use the ppc_md.get_rtc_time() et. al. 
> >>interfaces:
> >>1) They are called before the i2c driver is initialized and even 
> >>loaded
> >>if its a module.
> 
> There are three reasons.  You don't want to use an I2c rtc clock at
> all in these functions because they get can get called from the
> clock interrupt to update the time in the rtc.  If it does happen to 
> work,
> it creates long latencies in the timer interrupt.  If the i2c requires 
> an
> interrupt, they system will crash or hang.

I think one of us wasn't clear.  I'm not arguing for nuking
ppc_md.{get,set}_rtc_time(), I'm arguing for nuking
get_rtc_time()/set_rtc_time() inlines from <asm-ppc/rtc.h> (which are
used by drivers/char/genrtc.c) in favor of todc_time et al providing the
functions for genrtc.  So all of the other places we use
ppc_md.{get,set}_rtc_time() are unchanged.

-- 
Tom Rini
http://gate.crashing.org/~trini/