* Steven Rostedt | 2016-05-27 11:06:58 [-0400]: >You probably didn't remove it. It may have been removed a while ago >when Thomas did his big rewrite to get things working again. okay. As long as I don't lose patches :) >> about adding such a flag… I remember you had something in your tree to >> print from IRQ off regions via UART. > >I had a few hacks for a while, but they were nothing more than hacks. > >Perhaps we should make a better early_printk() or simple console for RT >that can handle printk in atomic locations. > >I have a hack patch that gives early_printk() a new "spin lock", where >it only takes the lock if the owner isn't on the CPU. Otherwise it >allows lock to continue (and wont release it). That hack was required >to get legible output from early_printk() when I was getting a bunch of >crashes on all the CPUs, because early_printk() has no locks, and the >console is just a mess when all CPUs print at once. An "atomic" console would be nice debugging wise. pstore with rawlocks would be available after a reboot if you can use pstore. And its overhead is probably not that huge. But its availability is limited. Another thing might be a dedicated 8250 UART console which would print in IRQ-off regions (and increase latency) but you would have the output which you wouldn't have otherwise (say from panic() handler). Anyway, nothing for production. Sebastian -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
