Messages in this thread | | | Subject | Re: [PATCH] tty/hvc/hvc_console: Fix wakeup of HVC thread on hvc_kick() | From | Benjamin Herrenschmidt <> | Date | Wed, 28 May 2014 10:01:30 +1000 |
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On Fri, 2014-05-23 at 19:41 +1000, Benjamin Herrenschmidt wrote: > Some backends call hvc_kick() to wakeup the HVC thread from its > slumber upon incoming characters. This however doesn't work > properly because it uses msleep_interruptible() which is mostly > immune to wake_up_process(). It will basically go back to sleep > until the timeout is expired (only signals can really wake it). > > Replace it with a simple shedule_timeout_interruptible() instead, > which may wakeup earlier every now and then but we really don't > care in this case.
Nobody commented ? :-)
Greg, do you want to take this in the tty tree or can I stick it in powerpc ?
Cheers, Ben
> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> > --- > drivers/tty/hvc/hvc_console.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/drivers/tty/hvc/hvc_console.c b/drivers/tty/hvc/hvc_console.c > index 94f9e3a..1094265 100644 > --- a/drivers/tty/hvc/hvc_console.c > +++ b/drivers/tty/hvc/hvc_console.c > @@ -760,10 +760,17 @@ static int khvcd(void *unused) > if (poll_mask == 0) > schedule(); > else { > + unsigned long j_timeout; > + > if (timeout < MAX_TIMEOUT) > timeout += (timeout >> 6) + 1; > > - msleep_interruptible(timeout); > + /* > + * We don't use msleep_interruptible otherwise > + * "kick" will fail to wake us up > + */ > + j_timeout = msecs_to_jiffies(timeout) + 1; > + schedule_timeout_interruptible(j_timeout); > } > } > __set_current_state(TASK_RUNNING); >
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