Re: [PATCH] ACPI / video: driver must be registered before checking for keypresses

[Jeremiah Mahler <jmmahler@gmail.com>]

all,

On Mon, Jan 04, 2016 at 11:22:28PM +0100, Adrien Schildknecht wrote:
> acpi_video_handles_brightness_key_presses() may use an uninitialized mutex.
> The error has been reported by lockdep: DEBUG_LOCKS_WARN_ON(l->magic != l).
> The function assumes that the video driver has been registered before being
> called. As explained in the comment of acpi_video_init(), the registration
> of the video class may be defered and thus may not take place in the init
> function of the module.
> 
> Use completion mechanisms to make sure that
> acpi_video_handles_brightness_key_presses() wait for the completion of
> acpi_video_register() before using the mutex.
> Also get rid of register_count since task completion can replace it.
> 
> Signed-off-by: Adrien Schildknecht <adrien+dev@schischi.me>
> ---
>  drivers/acpi/acpi_video.c | 27 ++++++++++++++-------------
>  1 file changed, 14 insertions(+), 13 deletions(-)
> 
[...]

This patch does fix the problem I was having [1].  Thanks for the fix.

  [1]: https://lkml.org/lkml/2016/1/4/791

Tested-by: Jeremiah Mahler <jmmahler@gmail.com>

-- 
- Jeremiah Mahler