[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>

arch/powerpc/platforms/powermac/backlight.c

@@ -15,6 +15,15 @@
 
 #define OLD_BACKLIGHT_MAX 15
 
+static void pmac_backlight_key_worker(void *data);
+static DECLARE_WORK(pmac_backlight_key_work, pmac_backlight_key_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
+ * notice the errors that might happen.
+ */
+static int pmac_backlight_key_queued;
+
 /* Protect the pmac_backlight variable */
 DEFINE_MUTEX(pmac_backlight_mutex);
 
@@ -71,7 +80,7 @@ int pmac_backlight_curve_lookup(struct fb_info *info, int value)
 	return level;
 }
 
-static void pmac_backlight_key(int direction)
+static void pmac_backlight_key_worker(void *data)
 {
 	mutex_lock(&pmac_backlight_mutex);
 	if (pmac_backlight) {
@@ -82,7 +91,8 @@ static void pmac_backlight_key(int direction)
 		props = pmac_backlight->props;
 
 		brightness = props->brightness +
-			((direction?-1:1) * (props->max_brightness / 15));
+			((pmac_backlight_key_queued?-1:1) *
+			 (props->max_brightness / 15));
 
 		if (brightness < 0)
 			brightness = 0;
@@ -97,14 +107,13 @@ static void pmac_backlight_key(int direction)
 	mutex_unlock(&pmac_backlight_mutex);
 }
 
-void pmac_backlight_key_up()
+void pmac_backlight_key(int direction)
 {
-	pmac_backlight_key(0);
-}
-
-void pmac_backlight_key_down()
-{
-	pmac_backlight_key(1);
+	/* we can receive multiple interrupts here, but the scheduled work
+	 * will run only once, with the last value
+	 */
+	pmac_backlight_key_queued = direction;
+	schedule_work(&pmac_backlight_key_work);
 }
 
 int pmac_backlight_set_legacy_brightness(int brightness)
@@ -157,3 +166,7 @@ int pmac_backlight_get_legacy_brightness()
 
 	return result;
 }
+
+EXPORT_SYMBOL_GPL(pmac_backlight);
+EXPORT_SYMBOL_GPL(pmac_backlight_mutex);
+EXPORT_SYMBOL_GPL(pmac_has_backlight_type);

drivers/macintosh/Kconfig

@@ -113,7 +113,10 @@ config PMAC_MEDIABAY
 
 config PMAC_BACKLIGHT
 	bool "Backlight control for LCD screens"
-	depends on ADB_PMU && (BROKEN || !PPC64)
+	depends on ADB_PMU && FB = y && (BROKEN || !PPC64)
+	select FB_BACKLIGHT
+	select BACKLIGHT_CLASS_DEVICE
+	select BACKLIGHT_LCD_SUPPORT
 	help
 	  Say Y here to enable Macintosh specific extensions of the generic
 	  backlight code. With this enabled, the brightness keys on older

drivers/video/aty/aty128fb.c

@@ -455,6 +455,7 @@ static void do_wait_for_fifo(u16 entries, struct aty128fb_par *par);
 static void wait_for_fifo(u16 entries, struct aty128fb_par *par);
 static void wait_for_idle(struct aty128fb_par *par);
 static u32 depth_to_dst(u32 depth);
+static void aty128_bl_set_power(struct fb_info *info, int power);
 
 #define BIOS_IN8(v)  	(readb(bios + (v)))
 #define BIOS_IN16(v) 	(readb(bios + (v)) | \
@@ -1257,25 +1258,11 @@ static void aty128_set_lcd_enable(struct aty128fb_par *par, int on)
 		reg &= ~LVDS_DISPLAY_DIS;
 		aty_st_le32(LVDS_GEN_CNTL, reg);
 #ifdef CONFIG_FB_ATY128_BACKLIGHT
-		mutex_lock(&info->bl_mutex);
-		if (info->bl_dev) {
-			down(&info->bl_dev->sem);
-			info->bl_dev->props->update_status(info->bl_dev);
-			up(&info->bl_dev->sem);
-		}
-		mutex_unlock(&info->bl_mutex);
+		aty128_bl_set_power(info, FB_BLANK_UNBLANK);
 #endif	
 	} else {
 #ifdef CONFIG_FB_ATY128_BACKLIGHT
-		mutex_lock(&info->bl_mutex);
-		if (info->bl_dev) {
-			down(&info->bl_dev->sem);
-			info->bl_dev->props->brightness = 0;
-			info->bl_dev->props->power = FB_BLANK_POWERDOWN;
-			info->bl_dev->props->update_status(info->bl_dev);
-			up(&info->bl_dev->sem);
-		}
-		mutex_unlock(&info->bl_mutex);
+		aty128_bl_set_power(info, FB_BLANK_POWERDOWN);
 #endif	
 		reg = aty_ld_le32(LVDS_GEN_CNTL);
 		reg |= LVDS_DISPLAY_DIS;
@@ -1702,17 +1689,16 @@ 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)
 {
 	struct fb_info *info = pci_get_drvdata(par->pdev);
 	int atylevel;
 
 	/* Get and convert the value */
-	mutex_lock(&info->bl_mutex);
 	atylevel = MAX_LEVEL -
 		(info->bl_curve[level] * FB_BACKLIGHT_MAX / MAX_LEVEL);
-	mutex_unlock(&info->bl_mutex);
 
 	if (atylevel < 0)
 		atylevel = 0;
@@ -1730,7 +1716,8 @@ static int aty128_bl_get_level_brightness(struct aty128fb_par *par,
 /* That one prevents proper CRT output with LCD off */
 #undef BACKLIGHT_DAC_OFF
 
-static int aty128_bl_update_status(struct backlight_device *bd)
+/* Call with fb_info->bl_mutex held */
+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);
@@ -1783,6 +1770,19 @@ 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;
@@ -1795,6 +1795,16 @@ static struct backlight_properties aty128_bl_data = {
 	.max_brightness	= (FB_BACKLIGHT_LEVELS - 1),
 };
 
+static void aty128_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;
+	__aty128_bl_update_status(info->bl_dev);
+	down(&info->bl_dev->sem);
+	mutex_unlock(&info->bl_mutex);
+}
+
 static void aty128_bl_init(struct aty128fb_par *par)
 {
 	struct fb_info *info = pci_get_drvdata(par->pdev);
@@ -2197,12 +2207,8 @@ static int aty128fb_blank(int blank, struct fb_info *fb)
 		return 0;
 
 #ifdef CONFIG_FB_ATY128_BACKLIGHT
-	if (machine_is(powermac) && blank) {
-		down(&fb->bl_dev->sem);
-		fb->bl_dev->props->power = FB_BLANK_POWERDOWN;
-		fb->bl_dev->props->update_status(fb->bl_dev);
-		up(&fb->bl_dev->sem);
-	}
+	if (machine_is(powermac) && blank)
+		aty128_bl_set_power(fb, FB_BLANK_POWERDOWN);
 #endif
 
 	if (blank & FB_BLANK_VSYNC_SUSPEND)
@@ -2218,14 +2224,12 @@ static int aty128fb_blank(int blank, struct fb_info *fb)
 		aty128_set_crt_enable(par, par->crt_on && !blank);
 		aty128_set_lcd_enable(par, par->lcd_on && !blank);
 	}
+
 #ifdef CONFIG_FB_ATY128_BACKLIGHT
-	if (machine_is(powermac) && !blank) {
-		down(&fb->bl_dev->sem);
-		fb->bl_dev->props->power = FB_BLANK_UNBLANK;
-		fb->bl_dev->props->update_status(fb->bl_dev);
-		up(&fb->bl_dev->sem);
-	}
+	if (machine_is(powermac) && !blank)
+		aty128_bl_set_power(fb, FB_BLANK_UNBLANK);
 #endif
+
 	return 0;
 }
 

drivers/video/aty/atyfb_base.c

@@ -2129,15 +2129,14 @@ static int atyfb_pci_resume(struct pci_dev *pdev)
 
 static struct backlight_properties aty_bl_data;
 
+/* Call with fb_info->bl_mutex held */
 static int aty_bl_get_level_brightness(struct atyfb_par *par, int level)
 {
 	struct fb_info *info = pci_get_drvdata(par->pdev);
 	int atylevel;
 
 	/* Get and convert the value */
-	mutex_lock(&info->bl_mutex);
 	atylevel = info->bl_curve[level] * FB_BACKLIGHT_MAX / MAX_LEVEL;
-	mutex_unlock(&info->bl_mutex);
 
 	if (atylevel < 0)
 		atylevel = 0;
@@ -2147,7 +2146,8 @@ static int aty_bl_get_level_brightness(struct atyfb_par *par, int level)
 	return atylevel;
 }
 
-static int aty_bl_update_status(struct backlight_device *bd)
+/* Call with fb_info->bl_mutex held */
+static int __aty_bl_update_status(struct backlight_device *bd)
 {
 	struct atyfb_par *par = class_get_devdata(&bd->class_dev);
 	unsigned int reg = aty_ld_lcd(LCD_MISC_CNTL, par);
@@ -2172,6 +2172,19 @@ static int aty_bl_update_status(struct backlight_device *bd)
 	return 0;
 }
 
+static int aty_bl_update_status(struct backlight_device *bd)
+{
+	struct atyfb_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 = __aty_bl_update_status(bd);
+	mutex_unlock(&info->bl_mutex);
+
+	return ret;
+}
+
 static int aty_bl_get_brightness(struct backlight_device *bd)
 {
 	return bd->props->brightness;
@@ -2184,6 +2197,16 @@ static struct backlight_properties aty_bl_data = {
 	.max_brightness = (FB_BACKLIGHT_LEVELS - 1),
 };
 
+static void aty_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;
+	__aty_bl_update_status(info->bl_dev);
+	down(&info->bl_dev->sem);
+	mutex_unlock(&info->bl_mutex);
+}
+
 static void aty_bl_init(struct atyfb_par *par)
 {
 	struct fb_info *info = pci_get_drvdata(par->pdev);
@@ -2790,16 +2813,8 @@ static int atyfb_blank(int blank, struct fb_info *info)
 		return 0;
 
 #ifdef CONFIG_PMAC_BACKLIGHT
-	if (machine_is(powermac) && blank > FB_BLANK_NORMAL) {
-		mutex_lock(&info->bl_mutex);
-		if (info->bl_dev) {
-			down(&info->bl_dev->sem);
-			info->bl_dev->props->power = FB_BLANK_POWERDOWN;
-			info->bl_dev->props->update_status(info->bl_dev);
-			up(&info->bl_dev->sem);
-		}
-		mutex_unlock(&info->bl_mutex);
-	}
+	if (machine_is(powermac) && blank > FB_BLANK_NORMAL)
+		aty_bl_set_power(info, FB_BLANK_POWERDOWN);
 #elif defined(CONFIG_FB_ATY_GENERIC_LCD)
 	if (par->lcd_table && blank > FB_BLANK_NORMAL &&
 	    (aty_ld_lcd(LCD_GEN_CNTL, par) & LCD_ON)) {
@@ -2830,16 +2845,8 @@ static int atyfb_blank(int blank, struct fb_info *info)
 	aty_st_le32(CRTC_GEN_CNTL, gen_cntl, par);
 
 #ifdef CONFIG_PMAC_BACKLIGHT
-	if (machine_is(powermac) && blank <= FB_BLANK_NORMAL) {
-		mutex_lock(&info->bl_mutex);
-		if (info->bl_dev) {
-			down(&info->bl_dev->sem);
-			info->bl_dev->props->power = FB_BLANK_UNBLANK;
-			info->bl_dev->props->update_status(info->bl_dev);
-			up(&info->bl_dev->sem);
-		}
-		mutex_unlock(&info->bl_mutex);
-	}
+	if (machine_is(powermac) && blank <= FB_BLANK_NORMAL)
+		aty_bl_set_power(info, FB_BLANK_UNBLANK);
 #elif defined(CONFIG_FB_ATY_GENERIC_LCD)
 	if (par->lcd_table && blank <= FB_BLANK_NORMAL &&
 	    (aty_ld_lcd(LCD_GEN_CNTL, par) & LCD_ON)) {

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

drivers/video/nvidia/nv_backlight.c

@@ -26,19 +26,19 @@
  */
 #define MIN_LEVEL 0x158
 #define MAX_LEVEL 0x534
+#define LEVEL_STEP ((MAX_LEVEL - MIN_LEVEL) / FB_BACKLIGHT_MAX)
 
 static struct backlight_properties nvidia_bl_data;
 
+/* Call with fb_info->bl_mutex held */
 static int nvidia_bl_get_level_brightness(struct nvidia_par *par,
 		int level)
 {
 	struct fb_info *info = pci_get_drvdata(par->pci_dev);
 	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;
@@ -50,7 +50,8 @@ static int nvidia_bl_get_level_brightness(struct nvidia_par *par,
 	return nlevel;
 }
 
-static int nvidia_bl_update_status(struct backlight_device *bd)
+/* Call with fb_info->bl_mutex held */
+static int __nvidia_bl_update_status(struct backlight_device *bd)
 {
 	struct nvidia_par *par = class_get_devdata(&bd->class_dev);
 	u32 tmp_pcrt, tmp_pmc, fpcontrol;
@@ -84,6 +85,19 @@ static int nvidia_bl_update_status(struct backlight_device *bd)
 	return 0;
 }
 
+static int nvidia_bl_update_status(struct backlight_device *bd)
+{
+	struct nvidia_par *par = class_get_devdata(&bd->class_dev);
+	struct fb_info *info = pci_get_drvdata(par->pci_dev);
+	int ret;
+
+	mutex_lock(&info->bl_mutex);
+	ret = __nvidia_bl_update_status(bd);
+	mutex_unlock(&info->bl_mutex);
+
+	return ret;
+}
+
 static int nvidia_bl_get_brightness(struct backlight_device *bd)
 {
 	return bd->props->brightness;
@@ -96,6 +110,16 @@ static struct backlight_properties nvidia_bl_data = {
 	.max_brightness = (FB_BACKLIGHT_LEVELS - 1),
 };
 
+void nvidia_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;
+	__nvidia_bl_update_status(info->bl_dev);
+	down(&info->bl_dev->sem);
+	mutex_unlock(&info->bl_mutex);
+}
+
 void nvidia_bl_init(struct nvidia_par *par)
 {
 	struct fb_info *info = pci_get_drvdata(par->pci_dev);