OMAP2+: PM/serial: hold console semaphore while OMAP UARTs are disabled
paul at pwsan.com
Thu Dec 2 02:23:57 EST 2010
On Thu, 25 Nov 2010, Jean Pihet wrote:
> On Thu, Nov 25, 2010 at 6:35 PM, Paul Walmsley <paul at pwsan.com> wrote:
> > On Thu, 25 Nov 2010, Jean Pihet wrote:
> >> On Thu, Nov 25, 2010 at 12:49 AM, Paul Walmsley <paul at pwsan.com> wrote:
> >> >
> >> > The console semaphore must be held while the OMAP UART devices are
> >> > disabled, lest a console write cause an ARM abort (and a kernel crash)
> >> > when the underlying console device is inaccessible. These crashes
> >> > only occur when the console is on one of the OMAP internal serial
> >> > ports.
> >> This does not fix the issue for me on Beagle (console on ttyO2).
> >> Doing:
> >> / # echo 5 > /sys/devices/platform/omap/omap-hsuart.0/sleep_timeout
> >> / # echo 5 > /sys/devices/platform/omap/omap-hsuart.1/sleep_timeout
> >> / # echo 5 > /sys/devices/platform/omap/omap-hsuart.2/sleep_timeout
> >> and waiting 5 seconds hangs the console.
> > By the way, you write that the above situation "hangs the console." Is it
> > just the case that the console dies and the rest of the system is still
> > alive, or does the whole system crash?
> The console hangs, the rest of the system still runs.
Just out of curiosity, if you send a few breaks to the OMAP over serial,
does that cause the console to pay attention again? CTRL-A F in minicom.
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