platform/x86: asus-wmi: use backlight_is_blank() for screenpad power

The screenpad backlight sets BL_CORE_SUSPENDRESUME, so the backlight
core calls update_status() on suspend, resume and fb blanking with
BL_CORE_SUSPENDED or BL_CORE_FBBLANK set in bd->props.state while
bd->props.power keeps its value: the switch on bd->props.power alone
ignored those flags, repowering the panel at suspend entry instead of
turning it off, and ignoring fb blank requests.

Replace the switch with backlight_is_blank(), which accounts for both
bd->props.power and bd->props.state: the panel is powered off whenever
the backlight is blank and powered on with backlight_get_brightness()
otherwise. Writing a power state other than BACKLIGHT_POWER_ON or
BACKLIGHT_POWER_OFF to bl_power now blanks the panel following the
core convention instead of warning and failing with -EINVAL.

The visible change is that the panel now actually powers off on
suspend and fb blank, and is restored on unblank and resume.

Suggested-by: Hugo Baigue <hugobaigue2004@gmail.com>
Closes: https://lore.kernel.org/all/CAO84+xJ9aW3pj3x8e9b5biWtnNd4EyH7A4Uy7aqBR4qZMDcVvg@mail.gmail.com/
Assisted-by: zcode:glm-5.3-flash
Signed-off-by: Denis Benato <denis.benato@linux.dev>
Link: https://patch.msgid.link/20260916143838.170950-4-denis.benato@linux.dev
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

0 files changed, 0 insertions, 0 deletions