From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: RFC: 405LP sleep From: Hollis Blanchard To: Todd Poynor Cc: devel list In-Reply-To: <3E023BD8.8050107@mvista.com> References: <1040330490.29647.340.camel@granite.austin.ibm.com> <3E023BD8.8050107@mvista.com> Content-Type: text/plain Date: 20 Dec 2002 17:31:14 -0600 Message-Id: <1040427074.1095.23.camel@granite.austin.ibm.com> Mime-Version: 1.0 Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: On Thu, 2002-12-19 at 15:36, Todd Poynor wrote: > > Suggest more unique names for these globals. Well, how about making them static? :) > + jiffies += rtc_secs_elapsed * HZ; > > If jiffies is jumped forward then can kernel events (such as those > waiting on a kernel timer) be missed? I certainly *hope* the check is >= rather than == ... :) > Whether or not timer queues et al > are processed on wakeup, not sure if it's harmful to update the "kernel > time" when the kernel has done nothing during the sleep interval, maybe > causing various timeouts. Has this been tried with applications like X > running and verified not to kill apps on wakeup? I have not run anything interesting like X, no. > Matt Locke and I have been discussing whether it's best to update wall > clock time but leave jiffies alone, since "kernel time" did not advance > during the sleep interval. It's a little worrisome: the kernel advances > time by 10ms for its own operations, but wallclock time (xtime and RTC) > jumps forward 10 minutes. We've tried this a little bit on a TI OMAP > and haven't seen anything die so far, but I imagine there'll be some > application that isn't happy about the situation no matter what choice > is made. Before posting I had tried commenting out the jiffies update and it seemed to run ok both ways. I decided to leave it in though to preserve the reality of time passing as much as possible. arch/arm/mach-sa1100/pm.c seems to only update xtime.tv_sec. I'm hoping Someone Who Knows will comment one way or the other here... The updated patch, with many cleanups and one important bugfix, has been posted to http://penguinppc.org/~hollis/405LP-sleep.diff. Aside from the remaining get_pteptr problem, I think the code is ready to be checked in. If anyone disagrees please let me know. :) -Hollis -- PowerPC Linux IBM Linux Technology Center ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/