[RFC] [PATCH] Adding ctrl-o sysrq hack support to 8250 driver

From: Sachin Sant (sachinp_at_in.ibm.com)
Date: 11/30/05

  • Next message: Johannes Berg: "Re: PowerBook5,8 - TrackPad update" 
    Date:	Wed, 30 Nov 2005 16:47:14 +0530
To: lkml <linux-kernel@vger.kernel.org>

    The following patch will allow a user to use sysrq keys over a serial
    console using the ctrl-o key sequence. This is similar to functionality
    provided by the hvc console drivers on PPC boxes.

    Signed-off-by: Sachin Sant <sachinp@in.ibm.com>

    diff -Naurp linux-2.6.14.3/drivers/serial/8250.c linux-2.6.14.3-new/drivers/serial/8250.c
    --- linux-2.6.14.3/drivers/serial/8250.c 2005-11-11 11:03:12.000000000 +0530
    +++ linux-2.6.14.3-new/drivers/serial/8250.c 2005-11-17 15:12:42.000000000 +0530
    @@ -1084,6 +1084,23 @@ receive_chars(struct uart_8250_port *up,
                              */
                     }
                     ch = serial_inp(up, UART_RX);
    +
    +#if defined(CONFIG_MAGIC_SYSRQ) && defined(CONFIG_SERIAL_CORE_CONSOLE)
    + /* Handle the SysRq ^O Hack */
    + if (ch == '\x0f') {
    + up->port.sysrq = jiffies + HZ*5;
    + goto ignore_char;
    + }
    + if (up->port.sysrq) {
    + int swallow;
    + spin_unlock(&up->port.lock);
    + swallow = uart_handle_sysrq_char(&up->port, ch, regs);
    + spin_lock(&up->port.lock);
    + if (swallow)
    + goto ignore_char;
    + }
    +#endif /* CONFIG_MAGIC_SYSRQ && CONFIG_SERIAL_CORE_CONSOLE */
    +
                     flag = TTY_NORMAL;
                     up->port.icount.rx++;
     

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