Re: [PATCH] dell: add new dell WMI format for the AIO machines

[Colin Ian King <colin.king@canonical.com>]

On 06/03/13 07:51, AceLan Kao wrote:
> There is a new DELL WMI spec. with new WMI event format.
> I'm working on the AIO machines, but I think the new format will apply to
> all the Dell's machines, not only for AIO, which will be released later
> this year.
>
> The new format of the WMI buffer is shown as below
> word 0 - the number of words following in the WMI buffer(not including
>          this word.
> word 1 - the event type
> 	0x0000 - A hot key is pressed or an event occurred
> 	0x000F - A sequence of hot keys are pressed
> word 2 and on - the event data
>
> Signed-off-by: AceLan Kao <acelan.kao@canonical.com>
> ---
>   drivers/platform/x86/dell-wmi-aio.c | 50 +++++++++++++++++++++++++++++++++----
>   1 file changed, 45 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/platform/x86/dell-wmi-aio.c b/drivers/platform/x86/dell-wmi-aio.c
> index 3f94545..d77fa86 100644
> --- a/drivers/platform/x86/dell-wmi-aio.c
> +++ b/drivers/platform/x86/dell-wmi-aio.c
> @@ -34,6 +34,14 @@ MODULE_LICENSE("GPL");
>   #define EVENT_GUID1 "284A0E6B-380E-472A-921F-E52786257FB4"
>   #define EVENT_GUID2 "02314822-307C-4F66-BF0E-48AEAEB26CC8"
>
> +struct dell_wmi_event {
> +	u16	length;
> +	/* 0x000: A hot key pressed or an event occurred
> +	 * 0x00F: A sequence of hot keys are pressed */
> +	u16	type;
> +	u16	event[];
> +};
> +
>   static const char *dell_wmi_aio_guids[] = {
>   	EVENT_GUID1,
>   	EVENT_GUID2,
> @@ -46,11 +54,35 @@ MODULE_ALIAS("wmi:"EVENT_GUID2);
>   static const struct key_entry dell_wmi_aio_keymap[] = {
>   	{ KE_KEY, 0xc0, { KEY_VOLUMEUP } },
>   	{ KE_KEY, 0xc1, { KEY_VOLUMEDOWN } },
> +	{ KE_KEY, 0xe030, { KEY_VOLUMEUP } },
> +	{ KE_KEY, 0xe02e, { KEY_VOLUMEDOWN } },
> +	{ KE_KEY, 0xe020, { KEY_MUTE } },
> +	{ KE_KEY, 0xe027, { KEY_DISPLAYTOGGLE } },
> +	{ KE_KEY, 0xe006, { KEY_BRIGHTNESSUP } },
> +	{ KE_KEY, 0xe005, { KEY_BRIGHTNESSDOWN } },
> +	{ KE_KEY, 0xe00b, { KEY_SWITCHVIDEOMODE } },
>   	{ KE_END, 0 }
>   };
>
>   static struct input_dev *dell_wmi_aio_input_dev;
>
> +/*
> + * The new WMI event data format will follow the dell_wmi_event structure
> + * So, we will check if the buffer matches the format
> + */
> +static bool dell_wmi_aio_event_check(u8 *buffer)
> +{
> +	dell_wmi_event *event = (dell_wmi_event *)buffer;
> +
> +	/* longest length is 6 right now */
> +	if (event->length > 10)
> +		return false;
> +	if (event->type != 0 && event->type != 0xf)
> +		return false;

This does assume that the buffer pointer is not null and long enough to 
access the event structure fields,  which may not be so in future 
firmware.  So, please check that the pointer is valid and the buffer is 
long enough.

> +
> +	return true;
> +}
> +
>   static void dell_wmi_aio_notify(u32 value, void *context)
>   {
>   	struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL };
> @@ -65,7 +97,7 @@ static void dell_wmi_aio_notify(u32 value, void *context)
>
>   	obj = (union acpi_object *)response.pointer;
>   	if (obj) {
> -		unsigned int scancode;
> +		unsigned int scancode = 0;
>
>   		switch (obj->type) {
>   		case ACPI_TYPE_INTEGER:
> @@ -75,13 +107,21 @@ static void dell_wmi_aio_notify(u32 value, void *context)
>   				scancode, 1, true);
>   			break;
>   		case ACPI_TYPE_BUFFER:
> -			/* Broken machines return the scancode in a buffer */
> -			if (obj->buffer.pointer && obj->buffer.length > 0) {
> -				scancode = obj->buffer.pointer[0];
> +			if (dell_wmi_aio_event_check(obj->buffer.pointer)) {
> +				dell_wmi_event *event =
> +					(dell_wmi_event *)obj->buffer.pointer;
> +				scancode = event->event[0];
> +			} else {
> +				/* Broken machines return the scancode in a
> +				   buffer */
> +				if (obj->buffer.pointer &&
> +						obj->buffer.length > 0)
> +					scancode = obj->buffer.pointer[0];
> +			}
> +			if (scancode)
>   				sparse_keymap_report_event(
>   					dell_wmi_aio_input_dev,
>   					scancode, 1, true);
> -			}
>   			break;
>   		}
>   	}
>