[PATCH] printk/of_serial: fix serial console cessation part way through boot.
geert at linux-m68k.org
Mon May 12 19:33:17 EST 2014
On Sat, May 10, 2014 at 7:37 AM, Stephen Chivers <schivers at csc.com> wrote:
> Commit 5f5c9ae56c38942623f69c3e6dc6ec78e4da2076
> "serial_core: Unregister console in uart_remove_one_port()"
> fixed a crash where a serial port was removed but
> not deregistered as a console.
> There is a side effect of that commit for platforms having serial consoles
> and of_serial configured (CONFIG_SERIAL_OF_PLATFORM). The serial console
> is disabled midway through the boot process.
> This cessation of the serial console affects PowerPC computers
> such as the MVME5100 and SAM440EP.
> The sequence is:
> bootconsole [udbg0] enabled
> serial8250/16550 driver initialises and registers its UARTS,
> one of these is the serial console.
> console [ttyS0] enabled
> of_serial probes "platform" devices, registering them as it goes.
> One of these is the serial console.
> console [ttyS0] disabled.
> The disabling of the serial console is due to:
> a. unregister_console in printk not clearing the
> CONS_ENABLED bit in the console flags,
> even though it has announced that the console is disabled; and
This part re-attaches the serial console on unbind/bind with the sh-sci driver,
too, which didn't work before. Cool, thanks!
> b. of_platform_serial_probe in of_serial not setting the port type
> before it registers with serial8250_register_8250_port.
This part I couldn't test.
> This patch ensures that the serial console is re-enabled when of_serial
> registers a serial port that corresponds to the designated console.
> Signed-off-by: Stephen Chivers <schivers at csc.com>
> Tested-by: Stephen Chivers <schivers at csc.com>
Acked-by: Geert Uytterhoeven <geert at linux-m68k.org> [unregister_console]
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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