[PATCH] Rewritten backlight infrastructure for portable Apple computers

This patch contains a total rewrite of the backlight infrastructure for
portable Apple computers.  Backward compatibility is retained.  A sysfs
interface allows userland to control the brightness with more steps than
before.  Userland is allowed to upload a brightness curve for different
monitors, similar to Mac OS X.

[akpm@osdl.org: add needed exports]
Signed-off-by: Michael Hanselmann <linux-kernel@hansmi.ch>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 12 insertions, 3 deletions

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 91a6e04d974..52f5659534f 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -32,6 +32,7 @@
 #include <linux/delay.h>
 #include <linux/kprobes.h>
 #include <linux/kexec.h>
+#include <linux/backlight.h>
 
 #include <asm/kdebug.h>
 #include <asm/pgtable.h>
@@ -105,10 +106,18 @@ int die(const char *str, struct pt_regs *regs, long err)
         spin_lock_irq(&die_lock);
         bust_spinlocks(1);
 #ifdef CONFIG_PMAC_BACKLIGHT
-        if (machine_is(powermac)) {
-                set_backlight_enable(1);
-                set_backlight_level(BACKLIGHT_MAX);
+        mutex_lock(&pmac_backlight_mutex);
+        if (machine_is(powermac) && pmac_backlight) {
+                struct backlight_properties *props;
+
+                down(&pmac_backlight->sem);
+                props = pmac_backlight->props;
+                props->brightness = props->max_brightness;
+                props->power = FB_BLANK_UNBLANK;
+                props->update_status(pmac_backlight);
+                up(&pmac_backlight->sem);
         }
+        mutex_unlock(&pmac_backlight_mutex);
 #endif
         printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
 #ifdef CONFIG_PREEMPT