backlight_device->sem has a very specific use as documented in the
header file. The external users of this are using it for a different
reason, to serialise access to the update_status() method.
backlight users were supposed to implement their own internal
serialisation of update_status() if needed but everyone is doing
things differently and incorrectly. Therefore add a global mutex to
take care of serialisation for everyone, once and for all.
Locking for get_brightness remains optional since most users don't
need it.
Also update the lcd class in a similar way.
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Remove uneeded owner field from backlight_properties structure.
Nothing uses it and it is unlikely that it will ever be used. The
backlight class uses other means to ensure that nothing references
unloaded code.
Based on a patch from Dmitry Torokhov <dtor@insightbb.com>
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Update the frambuffer drivers to the backlight_device_registers changes.
Signed-off-by: James Simmons <jsimmons@infradead.org>
Cc: Luming Yu <Luming.yu@intel.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
Fix some more problems (inverted use of semaphores in some places). He
also moved my checks into within the protected section which is better.
Signed-off-by: Michael Hanselmann <linux-kernel@hansmi.ch>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix a erroneous calculation of the legacy brightness values as reported by
Paul Collins. Additionally, it moves the calculation of the negative value
in the radeonfb driver after the value check.
Signed-off-by: Michael Hanselmann <linux-kernel@hansmi.ch>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Paul Collins <paul@briny.ondioline.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch contains a total rewrite of the backlight infrastructure for
portable Apple computers. Backward compatibility is retained. A sysfs
interface allows userland to control the brightness with more steps than
before. Userland is allowed to upload a brightness curve for different
monitors, similar to Mac OS X.
[akpm@osdl.org: add needed exports]
Signed-off-by: Michael Hanselmann <linux-kernel@hansmi.ch>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
