backlight: Rework backlight/fb interaction simplifying, lots

fb_info->bl_mutex is badly thought out and the backlight class doesn't
need it if the framebuffer/backlight register/unregister order is
consistent, particularly after the backlight locking fixes.

Fix the drivers to use the order:

backlight_device_register()
register_framebuffer()
unregister_framebuffer()
backlight_device_unregister()

and turn bl_mutex into a lock for the bl_curve data only.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>

1 files changed, 12 insertions, 43 deletions

diff --git a/drivers/video/aty/aty128fb.c b/drivers/video/aty/aty128fb.c
index 1c77cfb8e683..ef3e7861c27a 100644
--- a/drivers/video/aty/aty128fb.c
+++ b/drivers/video/aty/aty128fb.c
@@ -1697,7 +1697,6 @@ static int __devinit aty128fb_setup(char *options)
 
 static struct backlight_properties aty128_bl_data;
 
-/* Call with fb_info->bl_mutex held */
 static int aty128_bl_get_level_brightness(struct aty128fb_par *par,
                 int level)
 {
@@ -1705,6 +1704,7 @@ static int aty128_bl_get_level_brightness(struct aty128fb_par *par,
         int atylevel;
 
         /* Get and convert the value */
+        /* No locking of bl_curve since we read a single value */
         atylevel = MAX_LEVEL -
                 (info->bl_curve[level] * FB_BACKLIGHT_MAX / MAX_LEVEL);
 
@@ -1724,8 +1724,7 @@ static int aty128_bl_get_level_brightness(struct aty128fb_par *par,
 /* That one prevents proper CRT output with LCD off */
 #undef BACKLIGHT_DAC_OFF
 
-/* Call with fb_info->bl_mutex held */
-static int __aty128_bl_update_status(struct backlight_device *bd)
+static int aty128_bl_update_status(struct backlight_device *bd)
 {
         struct aty128fb_par *par = class_get_devdata(&bd->class_dev);
         unsigned int reg = aty_ld_le32(LVDS_GEN_CNTL);
@@ -1778,19 +1777,6 @@ static int __aty128_bl_update_status(struct backlight_device *bd)
         return 0;
 }
 
-static int aty128_bl_update_status(struct backlight_device *bd)
-{
-        struct aty128fb_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 = __aty128_bl_update_status(bd);
-        mutex_unlock(&info->bl_mutex);
-
-        return ret;
-}
-
 static int aty128_bl_get_brightness(struct backlight_device *bd)
 {
         return bd->props->brightness;
@@ -1804,14 +1790,10 @@ static struct backlight_properties aty128_bl_data = {
 
 static void aty128_bl_set_power(struct fb_info *info, int power)
 {
-        mutex_lock(&info->bl_mutex);
-
         if (info->bl_dev) {
                 info->bl_dev->props->power = power;
-                __aty128_bl_update_status(info->bl_dev);
+                backlight_update_status(info->bl_dev);
         }
-
-        mutex_unlock(&info->bl_mutex);
 }
 
 static void aty128_bl_init(struct aty128fb_par *par)
@@ -1838,12 +1820,10 @@ static void aty128_bl_init(struct aty128fb_par *par)
                 goto error;
         }
 
-        mutex_lock(&info->bl_mutex);
         info->bl_dev = bd;
         fb_bl_default_curve(info, 0,
                  63 * FB_BACKLIGHT_MAX / MAX_LEVEL,
                 219 * FB_BACKLIGHT_MAX / MAX_LEVEL);
-        mutex_unlock(&info->bl_mutex);
 
         bd->props->brightness = aty128_bl_data.max_brightness;
         bd->props->power = FB_BLANK_UNBLANK;
@@ -1864,31 +1844,19 @@ error:
         return;
 }
 
-static void aty128_bl_exit(struct aty128fb_par *par)
+static void aty128_bl_exit(struct backlight_device *bd)
 {
-        struct fb_info *info = pci_get_drvdata(par->pdev);
-
+        if (bd) {
 #ifdef CONFIG_PMAC_BACKLIGHT
-        mutex_lock(&pmac_backlight_mutex);
-#endif
-
-        mutex_lock(&info->bl_mutex);
-        if (info->bl_dev) {
-#ifdef CONFIG_PMAC_BACKLIGHT
-                if (pmac_backlight == info->bl_dev)
+                mutex_lock(&pmac_backlight_mutex);
+                if (pmac_backlight == bd)
                         pmac_backlight = NULL;
+                mutex_unlock(&pmac_backlight_mutex);
 #endif
-
-                backlight_device_unregister(info->bl_dev);
-                info->bl_dev = NULL;
+                backlight_device_unregister(bd);
 
                 printk("aty128: Backlight unloaded\n");
         }
-        mutex_unlock(&info->bl_mutex);
-
-#ifdef CONFIG_PMAC_BACKLIGHT
-        mutex_unlock(&pmac_backlight_mutex);
-#endif
 }
 #endif /* CONFIG_FB_ATY128_BACKLIGHT */
 
@@ -2175,11 +2143,12 @@ static void __devexit aty128_remove(struct pci_dev *pdev)
 
         par = info->par;
 
+        unregister_framebuffer(info);
+
 #ifdef CONFIG_FB_ATY128_BACKLIGHT
-        aty128_bl_exit(par);
+        aty128_bl_exit(info->bl_dev);
 #endif
 
-        unregister_framebuffer(info);
 #ifdef CONFIG_MTRR
         if (par->mtrr.vram_valid)
                 mtrr_del(par->mtrr.vram, info->fix.smem_start,