Re: PNP0501 serial driver takes almost 2 seconds to suspend/resume (printk issue)

From: Todd Brandt
Date: Wed Jul 13 2022 - 10:25:05 EST

On Wed, 2022-07-13 at 11:57 +0206, John Ogness wrote:
> On 2022-07-11, Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx> wrote:
> > > It seems that __pr_flush() does not check whether all consoles
> > > are
> > > suspended. In this case the progress is not possible and it has
> > > to
> > > wait the entire timeout.
> >
> > But isn't console_suspended set after pr_flush() call?
> There should not be any printing after the suspend_console() message.
> If
> Todd's report is coming from 5.19-rc1, then it is likely a kthread
> issue, where the kthread is not respecting @console_suspended. (This
> would still need to be fixed for the kthreads, but would not be
> relevant
> for 5.19.)
> John

It appears to still be there in rc5 (our lab system is usually 6 days
behind, so rc6 hasn't been run yet). I'm building a new rc6 kernel with
CONFIG_PRINTK_CALLER today and will run it on all affected machines,
I'll send out the data this afternoon Oregon Time. I'll include
timelines for all affected machines to give you a better sampling.