[PATCH] powermac: Combined fixes for backlight code

This patch fixes several problems:
- pmac_backlight_key() is called under interrupt context, and therefore
  can't use mutexes or semaphores, so defer the backlight level for
  later, as it's not critical (original code by Aristeu S. Rozanski F.
  <aris@valeta.org>).
- Add exports for functions that might be called from modules
- Fix Kconfig depdencies on PMAC_BACKLIGHT.
- Fix locking issues on calls from inside the driver (reported by
  Aristeu S. Rozanski F., too)
- Fix wrong calculation of backlight values in some of the drivers
- Replace pmac_backlight_key_up/down by inline functions

[akpm@osdl.org: fix function prototypes]
Signed-off-by: Michael Hanselmann <linux-kernel@hansmi.ch>
Acked-by: Aristeu S. Rozanski F. <aris@valeta.org>
Acked-by: Rene Nussbaumer <linux-kernel@killerfox.forkbomb.ch>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 1 insertions, 2 deletions

diff --git a/drivers/video/chipsfb.c b/drivers/video/chipsfb.c
index eba9d93ae360..73cb426bf2d7 100644
--- a/drivers/video/chipsfb.c
+++ b/drivers/video/chipsfb.c
@@ -149,12 +149,11 @@ static int chipsfb_blank(int blank, struct fb_info *info)
         mutex_lock(&pmac_backlight_mutex);
 
         if (pmac_backlight) {
-                down(&pmac_backlight->sem);
-
                 /* used to disable backlight only for blank > 1, but it seems
                  * useful at blank = 1 too (saves battery, extends backlight
                  * life)
                  */
+                down(&pmac_backlight->sem);
                 if (blank)
                         pmac_backlight->props->power = FB_BLANK_POWERDOWN;
                 else