[PATCH] powermac: More powermac backlight fixes

This patch fixes several problems:
- The legacy backlight value might be set at interrupt time. Introduced
  a worker to prevent it from directly calling the backlight code.
- via-pmu allows the backlight to be grabbed, in which case we need to
  prevent other kernel code from changing the brightness.
- Don't send PMU requests in via-pmu-backlight when the machine is about
  to sleep or waking up.
- More Kconfig fixes.

Signed-off-by: Michael Hanselmann <linux-kernel@hansmi.ch>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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, 55 insertions, 3 deletions

diff --git a/arch/powerpc/platforms/powermac/backlight.c b/arch/powerpc/platforms/powermac/backlight.c
index 74eed6b74cd6..d66415491055 100644
--- a/arch/powerpc/platforms/powermac/backlight.c
+++ b/arch/powerpc/platforms/powermac/backlight.c
@@ -10,19 +10,32 @@
 #include <linux/kernel.h>
 #include <linux/fb.h>
 #include <linux/backlight.h>
+#include <linux/adb.h>
+#include <linux/pmu.h>
+#include <asm/atomic.h>
 #include <asm/prom.h>
 #include <asm/backlight.h>
 
 #define OLD_BACKLIGHT_MAX 15
 
 static void pmac_backlight_key_worker(void *data);
+static void pmac_backlight_set_legacy_worker(void *data);
+
 static DECLARE_WORK(pmac_backlight_key_work, pmac_backlight_key_worker, NULL);
+static DECLARE_WORK(pmac_backlight_set_legacy_work, pmac_backlight_set_legacy_worker, NULL);
 
-/* Although this variable is used in interrupt context, it makes no sense to
- * protect it. No user is able to produce enough key events per second and
+/* Although these variables are used in interrupt context, it makes no sense to
+ * protect them. No user is able to produce enough key events per second and
  * notice the errors that might happen.
  */
 static int pmac_backlight_key_queued;
+static int pmac_backlight_set_legacy_queued;
+
+/* The via-pmu code allows the backlight to be grabbed, in which case the
+ * in-kernel control of the brightness needs to be disabled. This should
+ * only be used by really old PowerBooks.
+ */
+static atomic_t kernel_backlight_disabled = ATOMIC_INIT(0);
 
 /* Protect the pmac_backlight variable */
 DEFINE_MUTEX(pmac_backlight_mutex);
@@ -82,6 +95,9 @@ int pmac_backlight_curve_lookup(struct fb_info *info, int value)
 
 static void pmac_backlight_key_worker(void *data)
 {
+        if (atomic_read(&kernel_backlight_disabled))
+                return;
+
         mutex_lock(&pmac_backlight_mutex);
         if (pmac_backlight) {
                 struct backlight_properties *props;
@@ -107,8 +123,12 @@ static void pmac_backlight_key_worker(void *data)
         mutex_unlock(&pmac_backlight_mutex);
 }
 
+/* This function is called in interrupt context */
 void pmac_backlight_key(int direction)
 {
+        if (atomic_read(&kernel_backlight_disabled))
+                return;
+
         /* we can receive multiple interrupts here, but the scheduled work
          * will run only once, with the last value
          */
@@ -116,7 +136,7 @@ void pmac_backlight_key(int direction)
         schedule_work(&pmac_backlight_key_work);
 }
 
-int pmac_backlight_set_legacy_brightness(int brightness)
+static int __pmac_backlight_set_legacy_brightness(int brightness)
 {
         int error = -ENXIO;
 
@@ -145,6 +165,28 @@ int pmac_backlight_set_legacy_brightness(int brightness)
         return error;
 }
 
+static void pmac_backlight_set_legacy_worker(void *data)
+{
+        if (atomic_read(&kernel_backlight_disabled))
+                return;
+
+        __pmac_backlight_set_legacy_brightness(pmac_backlight_set_legacy_queued);
+}
+
+/* This function is called in interrupt context */
+void pmac_backlight_set_legacy_brightness_pmu(int brightness) {
+        if (atomic_read(&kernel_backlight_disabled))
+                return;
+
+        pmac_backlight_set_legacy_queued = brightness;
+        schedule_work(&pmac_backlight_set_legacy_work);
+}
+
+int pmac_backlight_set_legacy_brightness(int brightness)
+{
+        return __pmac_backlight_set_legacy_brightness(brightness);
+}
+
 int pmac_backlight_get_legacy_brightness()
 {
         int result = -ENXIO;
@@ -167,6 +209,16 @@ int pmac_backlight_get_legacy_brightness()
         return result;
 }
 
+void pmac_backlight_disable()
+{
+        atomic_inc(&kernel_backlight_disabled);
+}
+
+void pmac_backlight_enable()
+{
+        atomic_dec(&kernel_backlight_disabled);
+}
+
 EXPORT_SYMBOL_GPL(pmac_backlight);
 EXPORT_SYMBOL_GPL(pmac_backlight_mutex);
 EXPORT_SYMBOL_GPL(pmac_has_backlight_type);