andrzej zaborowski wrote: > First was when I was booting off the sd for the first time and the sd > had errors so the kernel loaded from nand okay and then init loaded > but then subsequent programs or scripts loaded corrupt and something > locked up, so I used the power button.
Hmm, and then you booted from NAND and went on to repair the uSD card using the system booted from NAND ? Thanks, that's indeed a case where there's a visible difference, because we wouldn't even reach the point where neodog is running, yet the kernel isn't completely dead yet. > Second time was when I was hacking the timers yesterday and apparently > I broke gettimeofday and one of the first processes hung waiting for > something, I used the power button (for kicks) and it worked. (99% of > the times I was just taking the battery out and wouldn't mind doing it > that time also) You're very brave to do this kind of low-level hacking without a debug board ;-) By the way, my solution for quickly resetting the Neo without too much physical effort is to just toggle the debug board reset: http://svn.openmoko.org/developers/werner/dbgrst/ I almost always keep the debug board attached, since I don't want to miss any clues printed on the serial console, and I also like to copy and paste printks for later reference (which I couldn't do if I only had them on the screen). > Something to consider is that Linux has something called SysRq key for > like 15 years and it's a similar concept. It's something that works > at all times even after the kernel panicked and nobody doubts its > usefulness. Yes, SysRq is pretty close to this. Even there, the low-level driver only provides the SysRq keycode, but it's higher-level code that decides what to do with it. But I take your point that this is still in the kernel, not in user space. How about the following compromise: we leave the power-down code in the kernel, but move it from the interrupt handler to a separate function (perhaps in a separate file as well) that just gets called on ONKEY/SECOND events and that's responsible for handling onkey_seconds and perhaps also PCF50633_F_PWR_PRESSED. That makes it easier to remove/restructure/etc. it in case there are objections or if a future use of the PCF50633 by us or others does not agree with this specific emergency shutdown mechanism. pcf50633_work should be broken down into more manageable pieces anyway, see CodingStyle, chapter 6. Does that sound good ? - Werner
