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path: root/drivers/video/backlight
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Diffstat (limited to 'drivers/video/backlight')
-rw-r--r--drivers/video/backlight/mbp_nvidia_bl.c33
1 files changed, 31 insertions, 2 deletions
diff --git a/drivers/video/backlight/mbp_nvidia_bl.c b/drivers/video/backlight/mbp_nvidia_bl.c
index ce09b83244ac..3bb4c0a50c62 100644
--- a/drivers/video/backlight/mbp_nvidia_bl.c
+++ b/drivers/video/backlight/mbp_nvidia_bl.c
@@ -36,6 +36,11 @@ struct dmi_match_data {
struct backlight_ops backlight_ops;
};
+/* Module parameters. */
+static int debug;
+module_param_named(debug, debug, int, 0644);
+MODULE_PARM_DESC(debug, "Set to one to enable debugging messages.");
+
/*
* Implementation for MacBooks with Intel chipset.
*/
@@ -43,6 +48,10 @@ static int intel_chipset_send_intensity(struct backlight_device *bd)
{
int intensity = bd->props.brightness;
+ if (debug)
+ printk(KERN_DEBUG "mbp_nvidia_bl: setting brightness to %d\n",
+ intensity);
+
outb(0x04 | (intensity << 4), 0xb3);
outb(0xbf, 0xb2);
return 0;
@@ -50,9 +59,17 @@ static int intel_chipset_send_intensity(struct backlight_device *bd)
static int intel_chipset_get_intensity(struct backlight_device *bd)
{
+ int intensity;
+
outb(0x03, 0xb3);
outb(0xbf, 0xb2);
- return inb(0xb3) >> 4;
+ intensity = inb(0xb3) >> 4;
+
+ if (debug)
+ printk(KERN_DEBUG "mbp_nvidia_bl: read brightness of %d\n",
+ intensity);
+
+ return intensity;
}
static const struct dmi_match_data intel_chipset_data = {
@@ -72,6 +89,10 @@ static int nvidia_chipset_send_intensity(struct backlight_device *bd)
{
int intensity = bd->props.brightness;
+ if (debug)
+ printk(KERN_DEBUG "mbp_nvidia_bl: setting brightness to %d\n",
+ intensity);
+
outb(0x04 | (intensity << 4), 0x52f);
outb(0xbf, 0x52e);
return 0;
@@ -79,9 +100,17 @@ static int nvidia_chipset_send_intensity(struct backlight_device *bd)
static int nvidia_chipset_get_intensity(struct backlight_device *bd)
{
+ int intensity;
+
outb(0x03, 0x52f);
outb(0xbf, 0x52e);
- return inb(0x52f) >> 4;
+ intensity = inb(0x52f) >> 4;
+
+ if (debug)
+ printk(KERN_DEBUG "mbp_nvidia_bl: read brightness of %d\n",
+ intensity);
+
+ return intensity;
}
static const struct dmi_match_data nvidia_chipset_data = {