when acpi=off is provided in bootarg, kernel crash with
[ 1.252739] BUG: kernel NULL pointer dereference, address: 0000000000000018
[ 1.258308] Call Trace:
[ 1.258490] ? acpi_walk_namespace+0x147/0x147
[ 1.258770] acpi_get_devices+0xe4/0x137
[ 1.258921] ? drm_core_init+0xc0/0xc0 [drm]
[ 1.259108] detect_thinkpad_privacy_screen+0x5e/0xa8 [drm]
[ 1.259337] drm_privacy_screen_lookup_init+0xe/0xe85 [drm]
The reason is that acpi_walk_namespace expects acpi related stuff
initialized but in fact it wouldn't when acpi is set to off. In this case
we should honor acpi=off in detect_thinkpad_privacy_screen().
Signed-off-by: Tong Zhang <ztong0001@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220123091004.763775-1-ztong0001@gmail.com
Add X86 specific arch init code, which fills the privacy-screen lookup
table by checking for various vendor specific ACPI interfaces for
controlling the privacy-screen.
This initial version only checks for the Lenovo Thinkpad specific ACPI
methods for privacy-screen control.
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211005202322.700909-4-hdegoede@redhat.com
