Add a blink driver for debugging
Simple driver that blinks the keyboard LEDs when loaded. Useful
for checking that the kernel is still alive or for crashdumping.
The kdump kernel currently typically doesn't give any feedback
on the screen because it often cannot reinitialize the graphics
state. This patch allows it to at least show blinking lights
like panic.
Signed-off-by: Andi Kleen <[email protected]>
---
drivers/misc/Kconfig | 9 +++++++++
drivers/misc/Makefile | 1 +
drivers/misc/blink.c | 26 ++++++++++++++++++++++++++
3 files changed, 36 insertions(+)
Index: linux/drivers/misc/Kconfig
===================================================================
--- linux.orig/drivers/misc/Kconfig
+++ linux/drivers/misc/Kconfig
@@ -107,4 +107,13 @@ config MSI_LAPTOP
If you have an MSI S270 laptop, say Y or M here.
+config BLINK
+ tristate "Keyboard blink driver"
+ help
+ Driver that when loaded will blink the keyboard LEDs continuously.
+ This is useful for debugging and for kernels that cannot necessarily
+ output something to the screen like kexec kernels to give the user
+ a visual indication that the kernel is doing something.
+
+
endmenu
Index: linux/drivers/misc/Makefile
===================================================================
--- linux.orig/drivers/misc/Makefile
+++ linux/drivers/misc/Makefile
@@ -11,3 +11,4 @@ obj-$(CONFIG_LKDTM) += lkdtm.o
obj-$(CONFIG_TIFM_CORE) += tifm_core.o
obj-$(CONFIG_TIFM_7XX1) += tifm_7xx1.o
obj-$(CONFIG_SGI_IOC4) += ioc4.o
+obj-$(CONFIG_BLINK) += blink.o
Index: linux/drivers/misc/blink.c
===================================================================
--- /dev/null
+++ linux/drivers/misc/blink.c
@@ -0,0 +1,26 @@
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/timer.h>
+#include <linux/jiffies.h>
+
+static void do_blink(unsigned long data);
+
+static DEFINE_TIMER(blink_timer, do_blink, 0 ,0);
+
+static void do_blink(unsigned long data)
+{
+ static long count;
+ panic_blink(count++);
+ blink_timer.expires = jiffies + msecs_to_jiffies(1);
+ add_timer(&blink_timer);
+}
+
+static int blink_init(void)
+{
+ printk(KERN_INFO "Enabling keyboard blinking\n");
+ do_blink(0);
+ return 0;
+}
+
+module_init(blink_init);
+
-
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