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    SubjectRe: [PATCH 1/2] acpi: video: add function to support unregister backlight
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    Hi Dmitry, 

    Thanks for your review and suggestions first!

    於 一,2013-04-22 於 21:12 -0700,Dmitry Torokhov 提到:
    > On Mon, Apr 22, 2013 at 08:39:15PM +0800, Chun-Yi Lee wrote:
    > > From: "Lee, Chun-Yi" <jlee@suse.com>
    > > +static acpi_status
    > > +find_video_unregister_backlight(acpi_handle handle, u32 lvl, void *context,
    > > + void **rv)
    > > +{
    > > + struct acpi_device *acpi_dev;
    > > + struct acpi_video_bus *video = NULL;
    >
    > Gratuitous initialization of local variables prevents compiler from
    > warning when you using variable uninitialized.

    Yes, I agreed should not put gratuitous initialization, I will remove it
    in v2 patch.

    >
    > > + struct acpi_video_device *dev, *next;
    > > +
    > > + if (acpi_bus_get_device(handle, &acpi_dev))
    > > + return AE_OK;
    > > +
    > > + if (!acpi_match_device_ids(acpi_dev, video_device_ids)) {
    > > + video = acpi_driver_data(acpi_dev);
    > > + acpi_video_bus_stop_devices(video);
    > > + mutex_lock(&video->device_list_lock);
    > > + list_for_each_entry_safe(dev, next, &video->video_device_list,
    > > + entry) {
    > > + if (dev->backlight) {
    > > + backlight_device_unregister(dev->backlight);
    > > + dev->backlight = NULL;
    > > + kfree(dev->brightness->levels);
    > > + kfree(dev->brightness);
    > > + }
    > > + }
    > > + mutex_unlock(&video->device_list_lock);
    > > + acpi_video_bus_start_devices(video);
    > > + }
    > > + return AE_OK;
    > > +}
    > > +
    > > +void acpi_video_backlight_unregister(void)
    > > +{
    > > + if (!register_count) {
    >
    > Locking? It looks like the rest of the driver ignores locking too...

    Did you mean locking video_device_list?

    The acpi/video locks video_device_list when add, remove and notify acpi
    video bus driver. It always do the mutex lock before control
    video_device_list, so I also add lock when unregister all backlight of
    devices.


    Thanks a lot!
    Joey Lee

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