cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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dual_accel_detect.h (1729B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2/*
      3 * Helper code to detect 360 degree hinges (yoga) style 2-in-1 devices using 2 accelerometers
      4 * to allow the OS to determine the angle between the display and the base of the device.
      5 *
      6 * On Windows these are read by a special HingeAngleService process which calls undocumented
      7 * ACPI methods, to let the firmware know if the 2-in-1 is in tablet- or laptop-mode.
      8 * The firmware may use this to disable the kbd and touchpad to avoid spurious input in
      9 * tablet-mode as well as to report SW_TABLET_MODE info to the OS.
     10 *
     11 * Since Linux does not call these undocumented methods, the SW_TABLET_MODE info reported
     12 * by various drivers/platform/x86 drivers is incorrect. These drivers use the detection
     13 * code in this file to disable SW_TABLET_MODE reporting to avoid reporting broken info
     14 * (instead userspace can derive the status itself by directly reading the 2 accels).
     15 */
     16
     17#include <linux/acpi.h>
     18#include <linux/i2c.h>
     19
     20static bool dual_accel_detect_bosc0200(void)
     21{
     22	struct acpi_device *adev;
     23	int count;
     24
     25	adev = acpi_dev_get_first_match_dev("BOSC0200", NULL, -1);
     26	if (!adev)
     27		return false;
     28
     29	count = i2c_acpi_client_count(adev);
     30
     31	acpi_dev_put(adev);
     32
     33	return count == 2;
     34}
     35
     36static bool dual_accel_detect(void)
     37{
     38	/* Systems which use a pair of accels with KIOX010A / KIOX020A ACPI ids */
     39	if (acpi_dev_present("KIOX010A", NULL, -1) &&
     40	    acpi_dev_present("KIOX020A", NULL, -1))
     41		return true;
     42
     43	/* Systems which use a single DUAL250E ACPI device to model 2 accels */
     44	if (acpi_dev_present("DUAL250E", NULL, -1))
     45		return true;
     46
     47	/* Systems which use a single BOSC0200 ACPI device to model 2 accels */
     48	if (dual_accel_detect_bosc0200())
     49		return true;
     50
     51	return false;
     52}