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Aaron Lu authored
commit 77076c7a upstream. Some of the Thinkpads' firmware will issue a backlight change request through i915 operation region unconditionally on AC plug/unplug, the backlight level used is arbitrary and thus should be ignored. This is handled by commit 0b9f7d93 (ACPI / i915: ignore firmware requests for backlight change). Then there is a Dell laptop whose vendor backlight interface also makes use of operation region to change backlight level and with the above commit, that interface no long works. The condition used to ignore the backlight change request from firmware is thus changed to: if the vendor backlight interface is not in use and the ACPI backlight interface is broken, we ignore the requests; oterwise, we keep processing them. Fixes: 0b9f7d93 (ACPI / i915: ignore firmware requests for backlight change) Link: https://lkml.org/lkml/2014/9/23/854Reported-and-tested-by:
Pali Rohár <pali.rohar@gmail.com> Signed-off-by:
Aaron Lu <aaron.lu@intel.com> Acked-by:
Daniel Vetter <daniel@ffwll.ch> Signed-off-by:
Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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