[RFC] Option to disable mapping genrtc calls to ppc_md calls
Tom Rini
trini at kernel.crashing.org
Wed Jan 19 05:13:30 EST 2005
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/
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