[PATCH] Add panic blinking to 2.6

From: Andi Kleen (ak_at_suse.de)
Date: 10/31/04

  • Next message: Linus Torvalds: "Re: Semaphore assembly-code bug" 
    Date:	Sun, 31 Oct 2004 02:36:49 +0100
To: akpm@osdl.org, linux-kernel@vger.kernel.org

    This patch readds the panic blinking that was in 2.4
    to 2.6. This is useful to see when you're in X that the
    machine has paniced

    It addresses previously criticism.
    It should work now when the keyboard interrupt is off.
    It doesn't fully emulate the handler, but has a timeout
    for this case.

    Signed-off-by: Andi Kleen <ak@suse.de>

    diff -u linux-2.6.9-work/drivers/input/serio/i8042.c-PANIC linux-2.6.9-work/drivers/input/serio/i8042.c
    --- linux-2.6.9-work/drivers/input/serio/i8042.c-PANIC 2004-10-19 01:55:13.000000000 +0200
    +++ linux-2.6.9-work/drivers/input/serio/i8042.c 2004-10-20 05:20:24.000000000 +0200
    @@ -887,6 +887,41 @@
             0
     };
     
    +static int blink_frequency = 500;
    +module_param_named(panicblink, blink_frequency, int, 0600);
    +
    +/* Catch the case when the kbd interrupt is off */
    +#define DELAY do { mdelay(1); if (++delay > 10) return delay; } while(0)
    +
    +/* Tell the user who may be running in X and not see the console that we have
    + panic'ed. This is to distingush panics from "real" lockups. */
    +static long i8042_panic_blink(long count)
    +{
    + long delay = 0;
    + static long last_blink;
    + static char led;
    + /* Roughly 1/2s frequency. KDB uses about 1s. Make sure it is
    + different. */
    + if (!blink_frequency)
    + return 0;
    + if (count - last_blink < blink_frequency)
    + return 0;
    + led ^= 0x01 | 0x04;
    + while (i8042_read_status() & I8042_STR_IBF)
    + DELAY;
    + i8042_write_data(0xed); /* set leds */
    + DELAY;
    + while (i8042_read_status() & I8042_STR_IBF)
    + DELAY;
    + DELAY;
    + i8042_write_data(led);
    + DELAY;
    + last_blink = count;
    + return delay;
    +}
    +
    +#undef DELAY
    +
     /*
      * Suspend/resume handlers for the new PM scheme (driver model)
      */
    @@ -1047,6 +1082,8 @@
     
             register_reboot_notifier(&i8042_notifier);
     
    + panic_blink = i8042_panic_blink;
    +
             return 0;
     }
     
    @@ -1077,6 +1114,8 @@
             driver_unregister(&i8042_driver);
     
             i8042_platform_exit();
    +
    + panic_blink = NULL;
     }
     
     module_init(i8042_init);
    diff -u linux-2.6.9-work/include/linux/kernel.h-PANIC linux-2.6.9-work/include/linux/kernel.h
    --- linux-2.6.9-work/include/linux/kernel.h-PANIC 2004-10-19 01:55:35.000000000 +0200
    +++ linux-2.6.9-work/include/linux/kernel.h 2004-10-20 05:17:55.000000000 +0200
    @@ -66,6 +66,7 @@
             })
     
     extern struct notifier_block *panic_notifier_list;
    +extern long (*panic_blink)(long time);
     NORET_TYPE void panic(const char * fmt, ...)
             __attribute__ ((NORET_AND format (printf, 1, 2)));
     asmlinkage NORET_TYPE void do_exit(long error_code)
    diff -u linux-2.6.9-work/kernel/panic.c-PANIC linux-2.6.9-work/kernel/panic.c
    --- linux-2.6.9-work/kernel/panic.c-PANIC 2004-10-19 01:55:36.000000000 +0200
    +++ linux-2.6.9-work/kernel/panic.c 2004-10-20 05:17:55.000000000 +0200
    @@ -37,6 +37,15 @@
     }
     __setup("panic=", panic_setup);
     
    +static long no_blink(long time)
    +{
    + return 0;
    +}
    +
    +/* Returns how long it waited in ms */
    +long (*panic_blink)(long time) = no_blink;
    +EXPORT_SYMBOL(panic_blink);
    +
     /**
      * panic - halt the system
      * @fmt: The text string to print
    @@ -49,6 +58,7 @@
      
     NORET_TYPE void panic(const char * fmt, ...)
     {
    + long i;
             static char buf[1024];
             va_list args;
     #if defined(CONFIG_ARCH_S390)
    @@ -70,15 +80,16 @@
     
             if (panic_timeout > 0)
             {
    - int i;
                     /*
                       * Delay timeout seconds before rebooting the machine.
                      * We can't use the "normal" timers since we just panicked..
                       */
                     printk(KERN_EMERG "Rebooting in %d seconds..",panic_timeout);
    - for (i = 0; i < panic_timeout; i++) {
    + for (i = 0; i < panic_timeout*1000; ) {
                             touch_nmi_watchdog();
    - mdelay(1000);
    + i += panic_blink(i);
    + mdelay(1);
    + i++;
                     }
                     /*
                      * Should we run the reboot notifier. For the moment Im
    @@ -99,8 +110,11 @@
             disabled_wait(caller);
     #endif
             local_irq_enable();
    - for (;;)
    - ;
    + for (i = 0;;) {
    + i += panic_blink(i);
    + mdelay(1);
    + i++;
    + }
     }
     
     EXPORT_SYMBOL(panic);
    -
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