On Thu, May 17, 2018 at 10:48 PM, Tony Lindgren <tony@xxxxxxxxxxx> wrote: > * Andy Shevchenko <andy.shevchenko@xxxxxxxxx> [180517 16:38]: >> On Thu, May 17, 2018 at 4:48 PM, Tony Lindgren <tony@xxxxxxxxxxx> wrote: >> > * Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> [180516 10:49]: >> > The idea breaking PM seems silly to me considering that we've had >> > it working for years already. >> >> Same question / note. World is much more complex than just being OMAP. > > Sorry but you are making assumptions about hardware being powered on > all the time. Nope, other way around. The so called "support" _prevents_ our hardware to go to sleep. So it's not breaking, it's fixing. It's pity that OMAP solution is just a hack. > It may have been a safe assumption up to mid-90's and might still be > valid assumption for hardware providing on MS-DOS boot floppy > compability. > > But that is not a safe assumption for Linux kernel at all. Especially > for console TX where there's no need to keep it powered unless there > is actually something to write. > > If there are runtime PM issues for consoles, let's just fix them. Yes, there is an issue to begin with, i.e. irq_safe hack. Removal of that hack reveals the real issues with the code. > Then for really seeing console messages on next reboot from a hung > system, CONFIG_PSTORE_CONSOLE option seems to do a very good job. How this helps to prevent a more serious system crashes during an attempt to power UART on? > With a warm reset after triggered by watchdog the console messages > are readable most of the time even when using DDR as the back end. Ditto. -- With Best Regards, Andy Shevchenko -- 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
