The patch titled
powermac: defer work in backlight key press (and export fixes)
has been added to the -mm tree. Its filename is
powermac-defer-work-in-backlight-key-press-and-export-fixes.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: powermac: defer work in backlight key press (and export fixes)
From: Michael Hanselmann <linux-kernel@xxxxxxxxx>
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 (code by Aristeu S. Rozanski F. <aris@xxxxxxxxxx>). Also,
it fixes exports and Kconfig depdencies.
Signed-off-by: Michael Hanselmann <linux-kernel@xxxxxxxxx>
Acked-by: Aristeu S. Rozanski F. <aris@xxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
arch/powerpc/platforms/powermac/backlight.c | 31 ++++++++++++------
drivers/macintosh/Kconfig | 5 ++
include/asm-powerpc/backlight.h | 9 +++--
3 files changed, 32 insertions(+), 13 deletions(-)
diff -puN arch/powerpc/platforms/powermac/backlight.c~powermac-defer-work-in-backlight-key-press-and-export-fixes arch/powerpc/platforms/powermac/backlight.c
--- a/arch/powerpc/platforms/powermac/backlight.c~powermac-defer-work-in-backlight-key-press-and-export-fixes
+++ a/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 f
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 direc
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 direc
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);
diff -puN drivers/macintosh/Kconfig~powermac-defer-work-in-backlight-key-press-and-export-fixes drivers/macintosh/Kconfig
--- a/drivers/macintosh/Kconfig~powermac-defer-work-in-backlight-key-press-and-export-fixes
+++ a/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
diff -puN include/asm-powerpc/backlight.h~powermac-defer-work-in-backlight-key-press-and-export-fixes include/asm-powerpc/backlight.h
--- a/include/asm-powerpc/backlight.h~powermac-defer-work-in-backlight-key-press-and-export-fixes
+++ a/include/asm-powerpc/backlight.h
@@ -16,13 +16,16 @@
extern struct backlight_device *pmac_backlight;
extern struct mutex pmac_backlight_mutex;
-extern void pmac_backlight_calc_curve(struct fb_info*);
extern int pmac_backlight_curve_lookup(struct fb_info *info, int value);
extern int pmac_has_backlight_type(const char *type);
-extern void pmac_backlight_key_up(void);
-extern void pmac_backlight_key_down(void);
+extern void pmac_backlight_key(int direction);
+
+#define pmac_backlight_key_up() \
+ do { pmac_backlight_key(0); } while(0);
+#define pmac_backlight_key_down() \
+ do { pmac_backlight_key(1); } while(0);
extern int pmac_backlight_set_legacy_brightness(int brightness);
extern int pmac_backlight_get_legacy_brightness(void);
_
Patches currently in -mm which might be from linux-kernel@xxxxxxxxx are
powermac-defer-work-in-backlight-key-press-and-export-fixes.patch
locking-fixes-for-powermac-backlight-infrastructure.patch
-
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