[PATCH] (oneiric) (drop after 3.0) Fix kernel oops when backlight off hotkey pushed

Ike Panhc ike.pan at canonical.com
Sun Sep 11 06:08:55 UTC 2011

There is a bug which will cause kernel panic has been found[1] and the revised
patch is on mailing list[2].

In ideapad_backlight_notify_power() when acpi_backlight=video, blightdev is
NULL and kernel panic happen when driver tries to access it. The best way to
solve this is to check blightdev at the top of the function.

Oneiric kernel will be freezed on September 15th and looks like this patch
will be merged into mainline after, but I strongly suggest to have this patch
before kernel freeze because this patch can prevent kernel panic when user hit
the backlight power hotkey.

[1] http://www.mail-archive.com/platform-driver-x86@vger.kernel.org/msg02340.html

[2] http://www.mail-archive.com/platform-driver-x86@vger.kernel.org/msg02343.html

The following changes since commit 6242e334ff8a9f1651c2515535d98485e343dcb1:

  UBUNTU: Ubuntu-3.0.0-10.16 (2011-09-02 09:18:31 -0700)

are available in the git repository at:
  git://kernel.ubuntu.com/ikepanhc/public.git ideapad-for-oneiric-fix

Rene Bolldorf (1):
  ideapad: Check if acpi already handle backlight power in
    'ideapad_backlight_notify_power' to avoid a page fault

 drivers/platform/x86/ideapad-laptop.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)


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