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Date: Wed, 10 Dec 2008 22:31:53 +0000
From: Richard Purdie <rpurdie@...ys.net>
To: Mario Schwalbe <schwalbe@....tu-dresden.de>
Cc: Matthew Garrett <mjg@...hat.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] video: mbp_nvidia_bl: Fix brightness after
suspend/hibernation
On Wed, 2008-12-10 at 21:30 +0100, Mario Schwalbe wrote:
> The mbp_nvidia_bl driver allows to change the display brightness on
> Apple MacBook Pro with Nvidia graphics adapters. However, after
> resuming from suspend the brightness is at its maximum instead of
> the last recently used value. This patch converts the driver into a
> platform_driver in order to register a resume hook to re-send brightness.
> In addition, resources will be allocated through platform_driver means
> instead of calling request_region/release_region directly.
I understand the problem, I'm not sure adding more platform devices and
drivers into the equation is a good way to solve it. I've been thinking
of adding suspend/resume support into the backlight core for a while and
this would solve this problem. How about the following patch (only
compile tested so far)?
diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
index 592d714..fc95829 100644
--- a/drivers/video/backlight/backlight.c
+++ b/drivers/video/backlight/backlight.c
@@ -40,6 +40,10 @@ static int fb_notifier_callback(struct notifier_block *self,
if (!bd->ops->check_fb ||
bd->ops->check_fb(evdata->info)) {
bd->props.fb_blank = *(int *)evdata->data;
+ if (bd->props.fb_blank == FB_BLANK_UNBLANK)
+ bd->props.flags &= ~BL_CORE_FBBLANK;
+ else
+ bd->props.flags |= BL_CORE_FBBLANK;
backlight_update_status(bd);
}
mutex_unlock(&bd->ops_lock);
@@ -167,6 +171,34 @@ static ssize_t backlight_show_actual_brightness(struct device *dev,
static struct class *backlight_class;
+static int backlight_suspend(struct device *dev, pm_message_t state)
+{
+ struct backlight_device *bd = to_backlight_device(dev);
+
+ if (bd->ops->flags & BL_CORE_SUSPENDRESUME) {
+ mutex_lock(&bd->ops_lock);
+ bd->props.flags |= BL_CORE_SUSPENDED;
+ backlight_update_status(bd);
+ mutex_unlock(&bd->ops_lock);
+ }
+
+ return 0;
+}
+
+static int backlight_resume(struct device *dev)
+{
+ struct backlight_device *bd = to_backlight_device(dev);
+
+ if (bd->ops->flags & BL_CORE_SUSPENDRESUME) {
+ mutex_lock(&bd->ops_lock);
+ bd->props.flags &= ~BL_CORE_SUSPENDED;
+ backlight_update_status(bd);
+ mutex_unlock(&bd->ops_lock);
+ }
+
+ return 0;
+}
+
static void bl_device_release(struct device *dev)
{
struct backlight_device *bd = to_backlight_device(dev);
@@ -283,6 +315,8 @@ static int __init backlight_class_init(void)
}
backlight_class->dev_attrs = bl_device_attributes;
+ backlight_class->suspend = backlight_suspend;
+ backlight_class->resume = backlight_resume;
return 0;
}
diff --git a/drivers/video/backlight/corgi_bl.c b/drivers/video/backlight/corgi_bl.c
index 4d4d037..02ff4bb 100644
--- a/drivers/video/backlight/corgi_bl.c
+++ b/drivers/video/backlight/corgi_bl.c
@@ -25,8 +25,7 @@ static struct backlight_device *corgi_backlight_device;
static struct generic_bl_info *bl_machinfo;
static unsigned long corgibl_flags;
-#define CORGIBL_SUSPENDED 0x01
-#define CORGIBL_BATTLOW 0x02
+#define CORGIBL_BATTLOW 0x01
static int corgibl_send_intensity(struct backlight_device *bd)
{
@@ -34,9 +33,9 @@ static int corgibl_send_intensity(struct backlight_device *bd)
if (bd->props.power != FB_BLANK_UNBLANK)
intensity = 0;
- if (bd->props.fb_blank != FB_BLANK_UNBLANK)
+ if (bd->props.flags & BL_CORE_FBBLANK)
intensity = 0;
- if (corgibl_flags & CORGIBL_SUSPENDED)
+ if (bd->props.flags & BL_CORE_SUSPENDED)
intensity = 0;
if (corgibl_flags & CORGIBL_BATTLOW)
intensity &= bl_machinfo->limit_mask;
@@ -51,29 +50,6 @@ static int corgibl_send_intensity(struct backlight_device *bd)
return 0;
}
-#ifdef CONFIG_PM
-static int corgibl_suspend(struct platform_device *pdev, pm_message_t state)
-{
- struct backlight_device *bd = platform_get_drvdata(pdev);
-
- corgibl_flags |= CORGIBL_SUSPENDED;
- backlight_update_status(bd);
- return 0;
-}
-
-static int corgibl_resume(struct platform_device *pdev)
-{
- struct backlight_device *bd = platform_get_drvdata(pdev);
-
- corgibl_flags &= ~CORGIBL_SUSPENDED;
- backlight_update_status(bd);
- return 0;
-}
-#else
-#define corgibl_suspend NULL
-#define corgibl_resume NULL
-#endif
-
static int corgibl_get_intensity(struct backlight_device *bd)
{
return corgibl_intensity;
@@ -95,6 +71,7 @@ EXPORT_SYMBOL(corgibl_limit_intensity);
static struct backlight_ops corgibl_ops = {
+ .flags = BL_CORE_SUSPENDRESUME,
.get_brightness = corgibl_get_intensity,
.update_status = corgibl_send_intensity,
};
@@ -144,8 +121,6 @@ static int corgibl_remove(struct platform_device *pdev)
static struct platform_driver corgibl_driver = {
.probe = corgibl_probe,
.remove = corgibl_remove,
- .suspend = corgibl_suspend,
- .resume = corgibl_resume,
.driver = {
.name = "generic-bl",
},
diff --git a/drivers/video/backlight/mbp_nvidia_bl.c b/drivers/video/backlight/mbp_nvidia_bl.c
index 06964af..f5bd0b4 100644
--- a/drivers/video/backlight/mbp_nvidia_bl.c
+++ b/drivers/video/backlight/mbp_nvidia_bl.c
@@ -70,6 +70,7 @@ static int mbp_get_intensity(struct backlight_device *bd)
}
static struct backlight_ops mbp_ops = {
+ .flags = BL_CORE_SUSPENDRESUME,
.get_brightness = mbp_get_intensity,
.update_status = mbp_send_intensity,
};
diff --git a/include/linux/backlight.h b/include/linux/backlight.h
index 1ee9488..516fbc7 100644
--- a/include/linux/backlight.h
+++ b/include/linux/backlight.h
@@ -31,6 +31,10 @@ struct backlight_device;
struct fb_info;
struct backlight_ops {
+ unsigned int flags;
+
+#define BL_CORE_SUSPENDRESUME (1 << 0)
+
/* Notify the backlight driver some property has changed */
int (*update_status)(struct backlight_device *);
/* Return the current backlight brightness (accounting for power,
@@ -52,6 +56,12 @@ struct backlight_properties {
int power;
/* FB Blanking active? (values as for power) */
int fb_blank;
+ /* Flags used to signal drivers of state changes */
+ unsigned int flags;
+
+#define BL_CORE_SUSPENDED (1 << 0) /* backlight is suspended */
+#define BL_CORE_FBBLANK (1 << 1) /* backlight is under an fb blank event */
+
};
struct backlight_device {
--
Richard Purdie
Intel Open Source Technology Centre
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