On Thu, 2009-07-16 at 06:11 +0800, Jesse Barnes wrote:
> Some drivers need to know when a lid event occurs and get the current
> status. This can be useful for when a platform firmware clobbers some
> hardware state at lid time, and a driver needs to restore things when
> the lid is opened again.
>
> Signed-off-by: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>
> ---
> drivers/acpi/button.c | 45 +++++++++++++++++++++++++++++++++++++++++++--
> include/acpi/button.h | 10 ++++++++++
> 2 files changed, 53 insertions(+), 2 deletions(-)
> create mode 100644 include/acpi/button.h
>
> diff --git a/drivers/acpi/button.c b/drivers/acpi/button.c
> index 9195deb..ebb593e 100644
> --- a/drivers/acpi/button.c
> +++ b/drivers/acpi/button.c
> @@ -113,6 +113,9 @@ static const struct file_operations acpi_button_state_fops = {
> .release = single_release,
> };
>
> +static BLOCKING_NOTIFIER_HEAD(acpi_lid_notifier);
> +static struct acpi_device *lid_device;
If the box is booted with ACPI disabled, the variable of lid_device
won't be initialized correctly. In such case when we call the function
of acpi_lid_open, we will access the uninitialized variable. This is
incorrect.
At the same time we should assume that the LID status is open.
> +
> /* --------------------------------------------------------------------------
> FS Interface (/proc)
> -------------------------------------------------------------------------- */
> @@ -229,11 +232,38 @@ static int acpi_button_remove_fs(struct acpi_device *device)
> /* --------------------------------------------------------------------------
> Driver Interface
> -------------------------------------------------------------------------- */
> +int acpi_lid_notifier_register(struct notifier_block *nb)
> +{
> + return blocking_notifier_chain_register(&acpi_lid_notifier, nb);
> +}
> +EXPORT_SYMBOL(acpi_lid_notifier_register);
> +
> +int acpi_lid_notifier_unregister(struct notifier_block *nb)
> +{
> + return blocking_notifier_chain_unregister(&acpi_lid_notifier, nb);
> +}
> +EXPORT_SYMBOL(acpi_lid_notifier_unregister);
> +
> +int acpi_lid_open(void)
> +{
> + acpi_status status;
> + unsigned long long state;
> +
> + status = acpi_evaluate_integer(lid_device->handle, "_LID", NULL,
> + &state);
> + if (ACPI_FAILURE(status))
> + return -ENODEV;
> +
> + return !!state;
> +}
> +EXPORT_SYMBOL(acpi_lid_open);
> +
> static int acpi_lid_send_state(struct acpi_device *device)
> {
> struct acpi_button *button = acpi_driver_data(device);
> unsigned long long state;
> acpi_status status;
> + int ret;
>
> status = acpi_evaluate_integer(device->handle, "_LID", NULL, &state);
> if (ACPI_FAILURE(status))
> @@ -242,7 +272,12 @@ static int acpi_lid_send_state(struct acpi_device *device)
> /* input layer checks if event is redundant */
> input_report_switch(button->input, SW_LID, !state);
> input_sync(button->input);
> - return 0;
> +
> + ret = blocking_notifier_call_chain(&acpi_lid_notifier, state, device);
> + if (ret == NOTIFY_DONE)
> + ret = blocking_notifier_call_chain(&acpi_lid_notifier, state,
> + device);
> + return ret;
> }
>
> static void acpi_button_notify(struct acpi_device *device, u32 event)
> @@ -364,8 +399,14 @@ static int acpi_button_add(struct acpi_device *device)
> error = input_register_device(input);
> if (error)
> goto err_remove_fs;
> - if (button->type == ACPI_BUTTON_TYPE_LID)
> + if (button->type == ACPI_BUTTON_TYPE_LID) {
> acpi_lid_send_state(device);
> + /*
> + * This assumes there's only one lid device, or if there are
> + * more we only care about the last one...
> + */
> + lid_device = device;
> + }
>
> if (device->wakeup.flags.valid) {
> /* Button's GPE is run-wake GPE */
> diff --git a/include/acpi/button.h b/include/acpi/button.h
> new file mode 100644
> index 0000000..bb643a7
> --- /dev/null
> +++ b/include/acpi/button.h
> @@ -0,0 +1,10 @@
> +#ifndef ACPI_BUTTON_H
> +#define ACPI_BUTTON_H
> +
> +#include <linux/notifier.h>
Maybe sometimes the CONFIG_ACPI is disabled in kernel configuration.
So it will be better that we define another function set when
CONFIG_ACPI is disabled in kernel configuration.
Thanks.
Yakui
> +
> +extern int acpi_lid_notifier_register(struct notifier_block *nb);
> +extern int acpi_lid_notifier_unregister(struct notifier_block *nb);
> +extern int acpi_lid_open(void);
> +
> +#endif /* ACPI_BUTTON_H */
--
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