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@xxxxxxxxxxxxxxx>
> ---
> .../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?
--
Pali Rohár
pali.rohar@xxxxxxxxx
