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| author | Michael Hanselmann <linux-kernel@hansmi.ch> | 2006-09-25 16:25:07 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-09-25 17:38:36 -0700 |
| commit | 25981de5b836581364612a4b1fe27db3b5d1f861 (patch) | |
| tree | 6dc66d33c8ffaca1faf84bca4707db429548422f | |
| parent | f3ef9ead31ae995251b420ac98398bd7545bf4e1 (diff) | |
| download | linux-25981de5b836581364612a4b1fe27db3b5d1f861.tar.gz linux-25981de5b836581364612a4b1fe27db3b5d1f861.tar.xz | |
[PATCH] backlight: fix oops in __mutex_lock_slowpath during head /sys/class/graphics/fb0/*
Seems like not all drivers use the framebuffer_alloc() function and won't
have an initialized mutex. But those don't have a backlight, anyway.
Signed-off-by: Michael Hanselmann <linux-kernel@hansmi.ch>
Cc: Olaf Hering <olaf@aepfle.de>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Daniel R Thompson <daniel.thompson@st.com>
Cc: Jon Smirl <jonsmirl@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | drivers/video/fbsysfs.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/video/fbsysfs.c b/drivers/video/fbsysfs.c index 4f78f234473d..c151dcf68786 100644 --- a/drivers/video/fbsysfs.c +++ b/drivers/video/fbsysfs.c @@ -397,6 +397,12 @@ static ssize_t store_bl_curve(struct class_device *class_device, u8 tmp_curve[FB_BACKLIGHT_LEVELS]; unsigned int i; + /* Some drivers don't use framebuffer_alloc(), but those also + * don't have backlights. + */ + if (!fb_info || !fb_info->bl_dev) + return -ENODEV; + if (count != (FB_BACKLIGHT_LEVELS / 8 * 24)) return -EINVAL; @@ -430,6 +436,12 @@ static ssize_t show_bl_curve(struct class_device *class_device, char *buf) ssize_t len = 0; unsigned int i; + /* Some drivers don't use framebuffer_alloc(), but those also + * don't have backlights. + */ + if (!fb_info || !fb_info->bl_dev) + return -ENODEV; + mutex_lock(&fb_info->bl_mutex); for (i = 0; i < FB_BACKLIGHT_LEVELS; i += 8) len += snprintf(&buf[len], PAGE_SIZE, |