> From: NeilBrown [mailto:neilb@xxxxxxx] > Sent: Monday, February 06, 2012 5:58 PM > To: Woodruff, Richard Apologies for mangled mails... I am years over due ditching current method. > I don't think it is really OK to drop chars on the UART-to-Debug console. > However it is OK to drop the BAUD rate to 57600 where we can wake up in > time > for to catch the first bit. So if you want power saving, drop the console > buad rate. > > So I would suggest: > - remove the autosuspend timeouts > - allow runtime_pm to shutdown the device when it is not open, or when > rate is 57600 or below, or when 'CREAD' is clear > - keep runtime_pm active whenever there are bytes in the output queue or > fifo Yes slower baud + use of flow control should help. OMAP4 is like 10x better than OMAP2 with OMAP3 in middle. > The only case that wouldn't support is when a device will wake up the SOC > by > sending a non-break character which it is OK to receive corrupted. The > tty > would have to be in !CREAD for that to happen, and then there would be no > way > for the app to know that a non-break character was received. > Would it be reasonable to treat any input while CREAD is clear as a break? Others would have to comment on this. I never took this step as I was ok with degradation on debug console. If ever I wanted better logs I tended to telnet/ssh in on a network port which was better at retry at higher level. Regards, Richard W. -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
