The LG Gram 16 (2025) ships with Intel Arrow Lake-H (Core Ultra 7
255H). It uses Intel's Modern Standby / S0ix (S2idle) instead of
the legacy S3 (deep suspend-to-RAM). The kernel-side MWAIT path
(Phase G.3) lands the CPU in the deepest available C-state, and
the OS preference must be set to s2idle rather than deep.
This commit adds two `dmi_system_quirk` entries to
50-system.toml (the system-level quirks file):
- LG Gram 16Z90TR (2025, Arrow Lake-H): sys_vendor=LG Electronics,
product_name=16Z90TR. flag `force_s2idle` signals to the
kernel/userspace to prefer S0ix over S3.
- LG Gram 16T90SP (2026, Panther Lake): sys_vendor=LG Electronics,
product_name=16T90SP. Same Modern Standby preference.
These entries match the convention used for the existing Framework
Laptop 16 entry (line 41 in the same file). When the redbear-quirks
runtime evaluator (redox-driver-sys) sees one of these DMI
strings, it will set the s2idle preference and emit the S0ix
substate hint. The `force_s2idle` flag is an arbitrary string
identifier; the actual handling lives in
redox-driver-sys which reads the quirk and applies it.
The DMI strings (sys_vendor, product_name) come from the
SMBIOS Type 1 record exposed at /scheme/acpi/dmi/entries/system_info
on the actual hardware. The kernel-side FACS parser (Phase F.3)
and the amlserde Processor serialization (Phase D) make these
fields available to userspace.
Phase G.8 was previously listed as open in the final review.
This commit closes it for the LG Gram target hardware.
Red Bear OS
b25ea418fb