platform/x86: Add Lenovo ThinkPad PrivacyGuard.
diff mbox series

Message ID 20190822114833.29885-1-alex@alexanderweb.de
State Accepted, archived
Delegated to: Andy Shevchenko
Headers show
Series
  • platform/x86: Add Lenovo ThinkPad PrivacyGuard.
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Commit Message

Alexander Schremmer Aug. 22, 2019, 11:48 a.m. UTC
This feature is found optionally in T480s, T490, T490s.

The feature is called lcdshadow and visible via
/proc/acpi/ibm/lcdshadow.

The ACPI methods \_SB.PCI0.LPCB.EC.HKEY.{GSSS,SSSS,TSSS,CSSS} are
available in these machines. They get, set, toggle or change the state
apparently.

The patch was tested on a 5.0 series kernel on a T480s.

Signed-off-by: Alexander Schremmer <alex@alexanderweb.de>
---
 .../admin-guide/laptops/thinkpad-acpi.rst     |  23 ++++
 drivers/platform/x86/thinkpad_acpi.c          | 112 ++++++++++++++++++
 2 files changed, 135 insertions(+)

Comments

Andy Shevchenko Sept. 7, 2019, 5:22 p.m. UTC | #1
On Thu, Aug 22, 2019 at 2:48 PM Alexander Schremmer
<alex@alexanderweb.de> wrote:
>
> This feature is found optionally in T480s, T490, T490s.
>
> The feature is called lcdshadow and visible via
> /proc/acpi/ibm/lcdshadow.
>
> The ACPI methods \_SB.PCI0.LPCB.EC.HKEY.{GSSS,SSSS,TSSS,CSSS} are
> available in these machines. They get, set, toggle or change the state
> apparently.
>
> The patch was tested on a 5.0 series kernel on a T480s.
>

Pushed to my review and testing queue, thanks!

> Signed-off-by: Alexander Schremmer <alex@alexanderweb.de>
> ---
>  .../admin-guide/laptops/thinkpad-acpi.rst     |  23 ++++
>  drivers/platform/x86/thinkpad_acpi.c          | 112 ++++++++++++++++++
>  2 files changed, 135 insertions(+)
>
> diff --git a/Documentation/admin-guide/laptops/thinkpad-acpi.rst b/Documentation/admin-guide/laptops/thinkpad-acpi.rst
> index adea0bf2acc5..822907dcc845 100644
> --- a/Documentation/admin-guide/laptops/thinkpad-acpi.rst
> +++ b/Documentation/admin-guide/laptops/thinkpad-acpi.rst
> @@ -49,6 +49,7 @@ detailed description):
>         - Fan control and monitoring: fan speed, fan enable/disable
>         - WAN enable and disable
>         - UWB enable and disable
> +       - LCD Shadow (PrivacyGuard) enable and disable
>
>  A compatibility table by model and feature is maintained on the web
>  site, http://ibm-acpi.sf.net/. I appreciate any success or failure
> @@ -1409,6 +1410,28 @@ Sysfs notes
>         Documentation/driver-api/rfkill.rst for details.
>
>
> +LCD Shadow control
> +------------------
> +
> +procfs: /proc/acpi/ibm/lcdshadow
> +
> +Some newer T480s and T490s ThinkPads provide a feature called
> +PrivacyGuard. By turning this feature on, the usable vertical and
> +horizontal viewing angles of the LCD can be limited (as if some privacy
> +screen was applied manually in front of the display).
> +
> +procfs notes
> +^^^^^^^^^^^^
> +
> +The available commands are::
> +
> +       echo '0' >/proc/acpi/ibm/lcdshadow
> +       echo '1' >/proc/acpi/ibm/lcdshadow
> +
> +The first command ensures the best viewing angle and the latter one turns
> +on the feature, restricting the viewing angles.
> +
> +
>  EXPERIMENTAL: UWB
>  -----------------
>
> diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
> index 7bde4640ef34..12bf573c6568 100644
> --- a/drivers/platform/x86/thinkpad_acpi.c
> +++ b/drivers/platform/x86/thinkpad_acpi.c
> @@ -9714,6 +9714,114 @@ static struct ibm_struct battery_driver_data = {
>         .exit = tpacpi_battery_exit,
>  };
>
> +/*************************************************************************
> + * LCD Shadow subdriver, for the Lenovo PrivacyGuard feature
> + */
> +
> +
> +static int lcdshadow_state;
> +
> +static int lcdshadow_on_off(bool state)
> +{
> +       acpi_handle set_shadow_handle;
> +       int output;
> +
> +       if (ACPI_FAILURE(acpi_get_handle(
> +                                       hkey_handle,
> +                                       "SSSS",
> +                                       &set_shadow_handle))) {
> +               pr_warn("Thinkpad ACPI has no %s interface.\n", "SSSS");
> +               return -EIO;
> +       }
> +
> +       if (!acpi_evalf(set_shadow_handle, &output, NULL, "dd", (int)state))
> +               return -EIO;
> +
> +       lcdshadow_state = state;
> +       return 0;
> +}
> +
> +static int lcdshadow_set(bool on)
> +{
> +       if (lcdshadow_state < 0)
> +               return lcdshadow_state;
> +       if (lcdshadow_state == on)
> +               return 0;
> +       return lcdshadow_on_off(on);
> +}
> +
> +static int tpacpi_lcdshadow_init(struct ibm_init_struct *iibm)
> +{
> +       acpi_handle get_shadow_handle;
> +       int output;
> +
> +       if (ACPI_FAILURE(acpi_get_handle(
> +                                       hkey_handle,
> +                                       "GSSS",
> +                                       &get_shadow_handle))) {
> +               lcdshadow_state = -ENODEV;
> +               return 0;
> +       }
> +
> +       if (!acpi_evalf(get_shadow_handle, &output, NULL, "dd", 0)) {
> +               lcdshadow_state = -EIO;
> +               return -EIO;
> +       }
> +       if (!(output & 0x10000)) {
> +               lcdshadow_state = -ENODEV;
> +               return 0;
> +       }
> +       lcdshadow_state = output & 0x1;
> +
> +       return 0;
> +}
> +
> +static void lcdshadow_resume(void)
> +{
> +       if (lcdshadow_state >= 0)
> +               lcdshadow_on_off(lcdshadow_state);
> +}
> +
> +static int lcdshadow_read(struct seq_file *m)
> +{
> +       if (lcdshadow_state < 0) {
> +               seq_puts(m, "status:\t\tnot supported\n");
> +       } else {
> +               seq_printf(m, "status:\t\t%d\n", lcdshadow_state);
> +               seq_puts(m, "commands:\t0, 1\n");
> +       }
> +
> +       return 0;
> +}
> +
> +static int lcdshadow_write(char *buf)
> +{
> +       char *cmd;
> +       int state = -1;
> +
> +       if (lcdshadow_state < 0)
> +               return -ENODEV;
> +
> +       while ((cmd = next_cmd(&buf))) {
> +               if (strlencmp(cmd, "0") == 0)
> +                       state = 0;
> +               else if (strlencmp(cmd, "1") == 0)
> +                       state = 1;
> +       }
> +
> +       if (state == -1)
> +               return -EINVAL;
> +
> +       return lcdshadow_set(state);
> +}
> +
> +static struct ibm_struct lcdshadow_driver_data = {
> +       .name = "lcdshadow",
> +       .resume = lcdshadow_resume,
> +       .read = lcdshadow_read,
> +       .write = lcdshadow_write,
> +};
> +
>  /****************************************************************************
>   ****************************************************************************
>   *
> @@ -10195,6 +10303,10 @@ static struct ibm_init_struct ibms_init[] __initdata = {
>                 .init = tpacpi_battery_init,
>                 .data = &battery_driver_data,
>         },
> +       {
> +               .init = tpacpi_lcdshadow_init,
> +               .data = &lcdshadow_driver_data,
> +       },
>  };
>
>  static int __init set_ibm_param(const char *val, const struct kernel_param *kp)
> --
> 2.20.1
>


--
With Best Regards,
Andy Shevchenko
Pali Rohár Oct. 25, 2019, 11:33 a.m. UTC | #2
On Thursday 22 August 2019 13:48:33 Alexander Schremmer wrote:
> This feature is found optionally in T480s, T490, T490s.
> 
> The feature is called lcdshadow and visible via
> /proc/acpi/ibm/lcdshadow.
> 
> The ACPI methods \_SB.PCI0.LPCB.EC.HKEY.{GSSS,SSSS,TSSS,CSSS} are
> available in these machines. They get, set, toggle or change the state
> apparently.
> 
> The patch was tested on a 5.0 series kernel on a T480s.
> 
> Signed-off-by: Alexander Schremmer <alex@alexanderweb.de>
> ---
>  .../admin-guide/laptops/thinkpad-acpi.rst     |  23 ++++
>  drivers/platform/x86/thinkpad_acpi.c          | 112 ++++++++++++++++++
>  2 files changed, 135 insertions(+)
> 
> diff --git a/Documentation/admin-guide/laptops/thinkpad-acpi.rst b/Documentation/admin-guide/laptops/thinkpad-acpi.rst
> index adea0bf2acc5..822907dcc845 100644
> --- a/Documentation/admin-guide/laptops/thinkpad-acpi.rst
> +++ b/Documentation/admin-guide/laptops/thinkpad-acpi.rst
> @@ -49,6 +49,7 @@ detailed description):
>  	- Fan control and monitoring: fan speed, fan enable/disable
>  	- WAN enable and disable
>  	- UWB enable and disable
> +	- LCD Shadow (PrivacyGuard) enable and disable
>  
>  A compatibility table by model and feature is maintained on the web
>  site, http://ibm-acpi.sf.net/. I appreciate any success or failure
> @@ -1409,6 +1410,28 @@ Sysfs notes
>  	Documentation/driver-api/rfkill.rst for details.
>  
>  
> +LCD Shadow control
> +------------------
> +
> +procfs: /proc/acpi/ibm/lcdshadow
> +
> +Some newer T480s and T490s ThinkPads provide a feature called
> +PrivacyGuard. By turning this feature on, the usable vertical and
> +horizontal viewing angles of the LCD can be limited (as if some privacy
> +screen was applied manually in front of the display).
> +
> +procfs notes
> +^^^^^^^^^^^^
> +
> +The available commands are::
> +
> +	echo '0' >/proc/acpi/ibm/lcdshadow
> +	echo '1' >/proc/acpi/ibm/lcdshadow
> +
> +The first command ensures the best viewing angle and the latter one turns
> +on the feature, restricting the viewing angles.
> +
> +
>  EXPERIMENTAL: UWB
>  -----------------

Hello! Is not the whole /proc/apci/ibm API for new things obsoleted or deprecated?
And should not rather it use platform driver in /sys/ (class?) namespace?
Andy Shevchenko Oct. 25, 2019, 3:14 p.m. UTC | #3
On Fri, Oct 25, 2019 at 2:33 PM Pali Rohár <pali.rohar@gmail.com> wrote:
> On Thursday 22 August 2019 13:48:33 Alexander Schremmer wrote:
> > This feature is found optionally in T480s, T490, T490s.
> >
> > The feature is called lcdshadow and visible via
> > /proc/acpi/ibm/lcdshadow.
> >
> > The ACPI methods \_SB.PCI0.LPCB.EC.HKEY.{GSSS,SSSS,TSSS,CSSS} are
> > available in these machines. They get, set, toggle or change the state
> > apparently.
> >
> > The patch was tested on a 5.0 series kernel on a T480s.

> > +     echo '0' >/proc/acpi/ibm/lcdshadow
> > +     echo '1' >/proc/acpi/ibm/lcdshadow

> Hello! Is not the whole /proc/apci/ibm API for new things obsoleted or deprecated?
> And should not rather it use platform driver in /sys/ (class?) namespace?

There is an ongoing discussion about API to this kind of devices
somewhere in GPU mailing lists.
This interface is custom and probably shall never have been appeared.
However no-one prevented this from happening.

Patch
diff mbox series

diff --git a/Documentation/admin-guide/laptops/thinkpad-acpi.rst b/Documentation/admin-guide/laptops/thinkpad-acpi.rst
index adea0bf2acc5..822907dcc845 100644
--- a/Documentation/admin-guide/laptops/thinkpad-acpi.rst
+++ b/Documentation/admin-guide/laptops/thinkpad-acpi.rst
@@ -49,6 +49,7 @@  detailed description):
 	- Fan control and monitoring: fan speed, fan enable/disable
 	- WAN enable and disable
 	- UWB enable and disable
+	- LCD Shadow (PrivacyGuard) enable and disable
 
 A compatibility table by model and feature is maintained on the web
 site, http://ibm-acpi.sf.net/. I appreciate any success or failure
@@ -1409,6 +1410,28 @@  Sysfs notes
 	Documentation/driver-api/rfkill.rst for details.
 
 
+LCD Shadow control
+------------------
+
+procfs: /proc/acpi/ibm/lcdshadow
+
+Some newer T480s and T490s ThinkPads provide a feature called
+PrivacyGuard. By turning this feature on, the usable vertical and
+horizontal viewing angles of the LCD can be limited (as if some privacy
+screen was applied manually in front of the display).
+
+procfs notes
+^^^^^^^^^^^^
+
+The available commands are::
+
+	echo '0' >/proc/acpi/ibm/lcdshadow
+	echo '1' >/proc/acpi/ibm/lcdshadow
+
+The first command ensures the best viewing angle and the latter one turns
+on the feature, restricting the viewing angles.
+
+
 EXPERIMENTAL: UWB
 -----------------
 
diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index 7bde4640ef34..12bf573c6568 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -9714,6 +9714,114 @@  static struct ibm_struct battery_driver_data = {
 	.exit = tpacpi_battery_exit,
 };
 
+/*************************************************************************
+ * LCD Shadow subdriver, for the Lenovo PrivacyGuard feature
+ */
+
+
+static int lcdshadow_state;
+
+static int lcdshadow_on_off(bool state)
+{
+	acpi_handle set_shadow_handle;
+	int output;
+
+	if (ACPI_FAILURE(acpi_get_handle(
+					hkey_handle,
+					"SSSS",
+					&set_shadow_handle))) {
+		pr_warn("Thinkpad ACPI has no %s interface.\n", "SSSS");
+		return -EIO;
+	}
+
+	if (!acpi_evalf(set_shadow_handle, &output, NULL, "dd", (int)state))
+		return -EIO;
+
+	lcdshadow_state = state;
+	return 0;
+}
+
+static int lcdshadow_set(bool on)
+{
+	if (lcdshadow_state < 0)
+		return lcdshadow_state;
+	if (lcdshadow_state == on)
+		return 0;
+	return lcdshadow_on_off(on);
+}
+
+static int tpacpi_lcdshadow_init(struct ibm_init_struct *iibm)
+{
+	acpi_handle get_shadow_handle;
+	int output;
+
+	if (ACPI_FAILURE(acpi_get_handle(
+					hkey_handle,
+					"GSSS",
+					&get_shadow_handle))) {
+		lcdshadow_state = -ENODEV;
+		return 0;
+	}
+
+	if (!acpi_evalf(get_shadow_handle, &output, NULL, "dd", 0)) {
+		lcdshadow_state = -EIO;
+		return -EIO;
+	}
+	if (!(output & 0x10000)) {
+		lcdshadow_state = -ENODEV;
+		return 0;
+	}
+	lcdshadow_state = output & 0x1;
+
+	return 0;
+}
+
+static void lcdshadow_resume(void)
+{
+	if (lcdshadow_state >= 0)
+		lcdshadow_on_off(lcdshadow_state);
+}
+
+static int lcdshadow_read(struct seq_file *m)
+{
+	if (lcdshadow_state < 0) {
+		seq_puts(m, "status:\t\tnot supported\n");
+	} else {
+		seq_printf(m, "status:\t\t%d\n", lcdshadow_state);
+		seq_puts(m, "commands:\t0, 1\n");
+	}
+
+	return 0;
+}
+
+static int lcdshadow_write(char *buf)
+{
+	char *cmd;
+	int state = -1;
+
+	if (lcdshadow_state < 0)
+		return -ENODEV;
+
+	while ((cmd = next_cmd(&buf))) {
+		if (strlencmp(cmd, "0") == 0)
+			state = 0;
+		else if (strlencmp(cmd, "1") == 0)
+			state = 1;
+	}
+
+	if (state == -1)
+		return -EINVAL;
+
+	return lcdshadow_set(state);
+}
+
+static struct ibm_struct lcdshadow_driver_data = {
+	.name = "lcdshadow",
+	.resume = lcdshadow_resume,
+	.read = lcdshadow_read,
+	.write = lcdshadow_write,
+};
+
 /****************************************************************************
  ****************************************************************************
  *
@@ -10195,6 +10303,10 @@  static struct ibm_init_struct ibms_init[] __initdata = {
 		.init = tpacpi_battery_init,
 		.data = &battery_driver_data,
 	},
+	{
+		.init = tpacpi_lcdshadow_init,
+		.data = &lcdshadow_driver_data,
+	},
 };
 
 static int __init set_ibm_param(const char *val, const struct kernel_param *kp)