[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, 30 insertions, 14 deletions

diff --git a/drivers/video/riva/fbdev.c b/drivers/video/riva/fbdev.c
index baf494c..33dddba 100644
--- a/drivers/video/riva/fbdev.c
+++ b/drivers/video/riva/fbdev.c
@@ -277,9 +277,11 @@ static const struct riva_regs reg_template = {
  */
 #define MIN_LEVEL 0x158
 #define MAX_LEVEL 0x534
+#define LEVEL_STEP ((MAX_LEVEL - MIN_LEVEL) / FB_BACKLIGHT_MAX)
 
 static struct backlight_properties riva_bl_data;
 
+/* Call with fb_info->bl_mutex held */
 static int riva_bl_get_level_brightness(struct riva_par *par,
 		int level)
 {
@@ -287,9 +289,7 @@ static int riva_bl_get_level_brightness(struct riva_par *par,
 	int nlevel;
 
 	/* Get and convert the value */
-	mutex_lock(&info->bl_mutex);
-	nlevel = info->bl_curve[level] * FB_BACKLIGHT_MAX / MAX_LEVEL;
-	mutex_unlock(&info->bl_mutex);
+	nlevel = MIN_LEVEL + info->bl_curve[level] * LEVEL_STEP;
 
 	if (nlevel < 0)
 		nlevel = 0;
@@ -301,7 +301,8 @@ static int riva_bl_get_level_brightness(struct riva_par *par,
 	return nlevel;
 }
 
-static int riva_bl_update_status(struct backlight_device *bd)
+/* Call with fb_info->bl_mutex held */
+static int __riva_bl_update_status(struct backlight_device *bd)
 {
 	struct riva_par *par = class_get_devdata(&bd->class_dev);
 	U032 tmp_pcrt, tmp_pmc;
@@ -326,6 +327,19 @@ static int riva_bl_update_status(struct backlight_device *bd)
 	return 0;
 }
 
+static int riva_bl_update_status(struct backlight_device *bd)
+{
+	struct riva_par *par = class_get_devdata(&bd->class_dev);
+	struct fb_info *info = pci_get_drvdata(par->pdev);
+	int ret;
+
+	mutex_lock(&info->bl_mutex);
+	ret = __riva_bl_update_status(bd);
+	mutex_unlock(&info->bl_mutex);
+
+	return ret;
+}
+
 static int riva_bl_get_brightness(struct backlight_device *bd)
 {
 	return bd->props->brightness;
@@ -338,6 +352,16 @@ static struct backlight_properties riva_bl_data = {
 	.max_brightness = (FB_BACKLIGHT_LEVELS - 1),
 };
 
+static void riva_bl_set_power(struct fb_info *info, int power)
+{
+	mutex_lock(&info->bl_mutex);
+	up(&info->bl_dev->sem);
+	info->bl_dev->props->power = power;
+	__riva_bl_update_status(info->bl_dev);
+	down(&info->bl_dev->sem);
+	mutex_unlock(&info->bl_mutex);
+}
+
 static void riva_bl_init(struct riva_par *par)
 {
 	struct fb_info *info = pci_get_drvdata(par->pdev);
@@ -418,6 +442,7 @@ static void riva_bl_exit(struct riva_par *par)
 #else
 static inline void riva_bl_init(struct riva_par *par) {}
 static inline void riva_bl_exit(struct riva_par *par) {}
+static inline void riva_bl_set_power(struct fb_info *info, int power) {}
 #endif /* CONFIG_FB_RIVA_BACKLIGHT */
 
 /* ------------------------------------------------------------------------- *
@@ -1336,16 +1361,7 @@ static int rivafb_blank(int blank, struct fb_info *info)
 	SEQout(par, 0x01, tmp);
 	CRTCout(par, 0x1a, vesa);
 
-#ifdef CONFIG_FB_RIVA_BACKLIGHT
-	mutex_lock(&info->bl_mutex);
-	if (info->bl_dev) {
-		down(&info->bl_dev->sem);
-		info->bl_dev->props->power = blank;
-		info->bl_dev->props->update_status(info->bl_dev);
-		up(&info->bl_dev->sem);
-	}
-	mutex_unlock(&info->bl_mutex);
-#endif
+	riva_bl_set_power(info, blank);
 
 	NVTRACE_LEAVE();