Anyone using SysRQ key sequences on console serial port ?

[Scott Wood]

On Sun, 2014-02-16 at 10:56 -0500, Paul Gortmaker wrote:
> On Fri, Feb 14, 2014 at 3:42 PM, John Donnelly <john.d at servergy.com> wrote:
> > Hi,
> >
> >  I tried using the SysRq hotkey sequence on a serial console -
> > 3.11.0-5-powerpc-e500mc system, by issuing a " break " and the system
> > immediately wedges after displaying "SysRQ : HELP : " using both "Putty" and
> > "Teraterm"  terminal emulators. I know the system is dead because my ssh
> > sessions stopped too.
> 
> Yes it does work -- or at least it _did_ work.  Make sure your dts has an entry
> 
>                         compatible = "fsl,ns16550", "ns16550";
> 
> since that enables a workaround I'd added for a hardware errata relating
> to sending breaks over the serial console.   What you describe above
> makes me think you aren't getting the workaround enabled.

Also make sure CONFIG_SERIAL_8250_FSL is enabled.

-Scott