Re: [PATCHv2] thinkpad_acpi: Implement tablet mode resolving using GMMS method

[Lyude Paul <lyude@redhat.com>]

Looks good to me

Reviewed-by: Lyude Paul <lyude@redhat.com>
On Tue, 2017-10-10 at 11:12 +0200, Benjamin Berg wrote:
> Many thinkpad laptops and convertibles provide the GMMS method to
> resolve how far the laptop has been opened and whether it has been
> converted into tablet mode. This allows reporting a more precise tablet
> mode state to userspace.
> 
> The current implementation only reports a summarized tablet mode state
> which is triggered as soon as the input devices become unusable as they
> are folded away from the display.
> 
> This will work on all models where the CMMD method was used previously and
> it may also work in other cases.
> 
> Thanks to Peter Zhang of Lenovo for providing information on how to use the
> GMMS method to query the tablet mode.
> 
> Signed-off-by: Benjamin Berg <bberg@redhat.com>
> Cc: Peter FP1 Zhang <zhangfp1@lenovo.com>
> Cc: Lyude Paul <lyude@redhat.com>
> 
> --
> 
> v2:
>  - It appears that mode 4 may also report the FLAT state. This has
>    been observed on an X1 Yoga 2nd Generation.
> ---
>  drivers/platform/x86/thinkpad_acpi.c | 135 +++++++++++++++++++++++++++++++-
> ---
>  1 file changed, 122 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/platform/x86/thinkpad_acpi.c
> b/drivers/platform/x86/thinkpad_acpi.c
> index 2242d6035d9e..298a0088eb0c 100644
> --- a/drivers/platform/x86/thinkpad_acpi.c
> +++ b/drivers/platform/x86/thinkpad_acpi.c
> @@ -310,8 +310,7 @@ static struct {
>  	enum {
>  		TP_HOTKEY_TABLET_NONE = 0,
>  		TP_HOTKEY_TABLET_USES_MHKG,
> -		/* X1 Yoga 2016, seen on BIOS N1FET44W */
> -		TP_HOTKEY_TABLET_USES_CMMD,
> +		TP_HOTKEY_TABLET_USES_GMMS,
>  	} hotkey_tablet;
>  	u32 kbdlight:1;
>  	u32 light:1;
> @@ -2044,8 +2043,28 @@ static void hotkey_poll_setup(const bool may_warn);
>  
>  /* HKEY.MHKG() return bits */
>  #define TP_HOTKEY_TABLET_MASK (1 << 3)
> -/* ThinkPad X1 Yoga (2016) */
> -#define TP_EC_CMMD_TABLET_MODE 0x6
> +enum {
> +	TP_ACPI_MULTI_MODE_INVALID	= 0,
> +	TP_ACPI_MULTI_MODE_UNKNOWN	= 1 << 0,
> +	TP_ACPI_MULTI_MODE_LAPTOP	= 1 << 1,
> +	TP_ACPI_MULTI_MODE_TABLET	= 1 << 2,
> +	TP_ACPI_MULTI_MODE_FLAT		= 1 << 3,
> +	TP_ACPI_MULTI_MODE_STAND	= 1 << 4,
> +	TP_ACPI_MULTI_MODE_TENT		= 1 << 5,
> +	TP_ACPI_MULTI_MODE_STAND_TENT	= 1 << 6,
> +};
> +
> +enum {
> +	/* The following modes are considered tablet mode for the purpose
> of
> +	 * reporting the status to userspace. i.e. in all these modes it
> makes
> +	 * sense to disable the laptop input devices such as touchpad and
> +	 * keyboard.
> +	 */
> +	TP_ACPI_MULTI_MODE_TABLET_LIKE	= TP_ACPI_MULTI_MODE_TABLET |
> +					  TP_ACPI_MULTI_MODE_STAND |
> +					  TP_ACPI_MULTI_MODE_TENT |
> +					  TP_ACPI_MULTI_MODE_STAND_TENT,
> +};
>  
>  static int hotkey_get_wlsw(void)
>  {
> @@ -2066,6 +2085,93 @@ static int hotkey_get_wlsw(void)
>  	return (status) ? TPACPI_RFK_RADIO_ON : TPACPI_RFK_RADIO_OFF;
>  }
>  
> +static int hotkey_gmms_get_tablet_mode(int s, int *has_tablet_mode)
> +{
> +	int type = (s >> 16) & 0xffff;
> +	int value = s & 0xffff;
> +	int mode = TP_ACPI_MULTI_MODE_INVALID;
> +	int valid_modes = 0;
> +
> +	if (has_tablet_mode)
> +		*has_tablet_mode = 0;
> +
> +	switch (type) {
> +	case 1:
> +		valid_modes = TP_ACPI_MULTI_MODE_LAPTOP |
> +			      TP_ACPI_MULTI_MODE_TABLET |
> +			      TP_ACPI_MULTI_MODE_STAND_TENT;
> +		break;
> +	case 2:
> +		valid_modes = TP_ACPI_MULTI_MODE_LAPTOP |
> +			      TP_ACPI_MULTI_MODE_FLAT |
> +			      TP_ACPI_MULTI_MODE_TABLET |
> +			      TP_ACPI_MULTI_MODE_STAND |
> +			      TP_ACPI_MULTI_MODE_TENT;
> +		break;
> +	case 3:
> +		valid_modes = TP_ACPI_MULTI_MODE_LAPTOP |
> +			      TP_ACPI_MULTI_MODE_FLAT;
> +		break;
> +	case 4:
> +		/* Flat mode is included here as it can be seen at least
> +		 * on the X1 Yoga 2nd Gen. */
> +		valid_modes = TP_ACPI_MULTI_MODE_LAPTOP |
> +			      TP_ACPI_MULTI_MODE_FLAT |
> +			      TP_ACPI_MULTI_MODE_TABLET |
> +			      TP_ACPI_MULTI_MODE_STAND |
> +			      TP_ACPI_MULTI_MODE_TENT;
> +		break;
> +	case 5:
> +		valid_modes = TP_ACPI_MULTI_MODE_LAPTOP |
> +			      TP_ACPI_MULTI_MODE_FLAT |
> +			      TP_ACPI_MULTI_MODE_TABLET |
> +			      TP_ACPI_MULTI_MODE_STAND |
> +			      TP_ACPI_MULTI_MODE_TENT;
> +		break;
> +	default:
> +		pr_err("Unknown multi mode status type %d with value
> 0x%04X, please report this to %s\n",
> +		       type, value, TPACPI_MAIL);
> +		return 0;
> +	}
> +
> +	if (has_tablet_mode && (valid_modes &
> TP_ACPI_MULTI_MODE_TABLET_LIKE))
> +		*has_tablet_mode = 1;
> +
> +	switch (value) {
> +	case 1:
> +		mode = TP_ACPI_MULTI_MODE_LAPTOP;
> +		break;
> +	case 2:
> +		mode = TP_ACPI_MULTI_MODE_FLAT;
> +		break;
> +	case 3:
> +		mode = TP_ACPI_MULTI_MODE_TABLET;
> +		break;
> +	case 4:
> +		if (type == 1)
> +			mode = TP_ACPI_MULTI_MODE_STAND_TENT;
> +		else
> +			mode = TP_ACPI_MULTI_MODE_STAND;
> +		break;
> +	case 5:
> +		mode = TP_ACPI_MULTI_MODE_TENT;
> +		break;
> +	default:
> +		if (type == 5 && value == 0xffff) {
> +			pr_warn("Multi mode status is undetected, assuming
> laptop\n");
> +			return 0;
> +		}
> +	}
> +
> +	if (!(mode & valid_modes)) {
> +		pr_err("Unknown/reserved multi mode value 0x%04X for type
> %d, please report this to %s\n",
> +		       value, type, TPACPI_MAIL);
> +		return 0;
> +	}
> +
> +	return !!(mode & TP_ACPI_MULTI_MODE_TABLET_LIKE);
> +}
> +
>  static int hotkey_get_tablet_mode(int *status)
>  {
>  	int s;
> @@ -2077,11 +2183,11 @@ static int hotkey_get_tablet_mode(int *status)
>  
>  		*status = ((s & TP_HOTKEY_TABLET_MASK) != 0);
>  		break;
> -	case TP_HOTKEY_TABLET_USES_CMMD:
> -		if (!acpi_evalf(ec_handle, &s, "CMMD", "d"))
> +	case TP_HOTKEY_TABLET_USES_GMMS:
> +		if (!acpi_evalf(hkey_handle, &s, "GMMS", "dd", 0))
>  			return -EIO;
>  
> -		*status = (s == TP_EC_CMMD_TABLET_MODE);
> +		*status = hotkey_gmms_get_tablet_mode(s, NULL);
>  		break;
>  	default:
>  		break;
> @@ -3113,16 +3219,19 @@ static int hotkey_init_tablet_mode(void)
>  	int in_tablet_mode = 0, res;
>  	char *type = NULL;
>  
> -	if (acpi_evalf(hkey_handle, &res, "MHKG", "qd")) {
> +	if (acpi_evalf(hkey_handle, &res, "GMMS", "qdd", 0)) {
> +		int has_tablet_mode;
> +
> +		in_tablet_mode = hotkey_gmms_get_tablet_mode(res,
> +							     &has_tablet_mo
> de);
> +		if (has_tablet_mode)
> +			tp_features.hotkey_tablet =
> TP_HOTKEY_TABLET_USES_GMMS;
> +		type = "GMMS";
> +	} else if (acpi_evalf(hkey_handle, &res, "MHKG", "qd")) {
>  		/* For X41t, X60t, X61t Tablets... */
>  		tp_features.hotkey_tablet = TP_HOTKEY_TABLET_USES_MHKG;
>  		in_tablet_mode = !!(res & TP_HOTKEY_TABLET_MASK);
>  		type = "MHKG";
> -	} else if (acpi_evalf(ec_handle, &res, "CMMD", "qd")) {
> -		/* For X1 Yoga (2016) */
> -		tp_features.hotkey_tablet = TP_HOTKEY_TABLET_USES_CMMD;
> -		in_tablet_mode = res == TP_EC_CMMD_TABLET_MODE;
> -		type = "CMMD";
>  	}
>  
>  	if (!tp_features.hotkey_tablet)