summaryrefslogtreecommitdiff
path: root/Documentation/admin-guide/laptops/thinkpad-acpi.rst
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/admin-guide/laptops/thinkpad-acpi.rst')
-rw-r--r--Documentation/admin-guide/laptops/thinkpad-acpi.rst23
1 files changed, 23 insertions, 0 deletions
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
-----------------