[PATCH v3] ACPI: x86: Disable wakeup on MSI MS-1592 and MS-1594 dGPU root port

[Victor Carreras <vicajilau@gmail.com>]

On MSI Summit E16 Flip A12UCT (motherboard MS-1592, BIOS E1592IMS.111)
and MSI Prestige 16 Studio A13VE / Summit E16 Flip A13VET (motherboard
MS-1594, BIOS E1594IMS.115), the I2C touchpad (ELAN0305:00, 04F3:31FD)
permanently stops generating interrupts as soon as the discrete NVIDIA
GPU (0000:01:00.0) and its parent PCIe Root Port (0000:00:06.0,
\_SB.PC00.PEG0) enter D3cold.

In the platform's SSDT (MSI_NB / AdlP_Rvp), \_SB.PC00.PEG0 sets its wake
GPIO (WAKG) from the BIOS NVS variable P1WP, which erroneously points to
GPP_A20 (INTC1055:00 pin 62) -- the GPIO interrupt line wired to the
touchpad.

During boot, \_SB.PC00.PEG0.PON() calls \_SB.SHPO(WAKG, One), setting
PAD_CFG0_GPP_A20.GPIROUTSCI = 0 and HostSwOwn = 1 so the OS GPIO driver
owns the pin. However, when the root port runtime-suspends to D3cold,
Linux enables ACPI wakeup via \_SB.PC00.PEG0._DSW(1, 0, 3), which sets
WKEN = 1. Subsequent evaluation of \_SB.PC00.PEG0.PXP._OFF -> POFF()
executes:

  If (CondRefOf (WAKG))
  {
      If (((WAKG != Zero) && WKEN))
      {
          \_SB.SHPO (WAKG, Zero)
      }
  }

This switches GPP_A20 ownership to ACPI GPE mode (HostSwOwn = 0,
GPIROUTSCI = 1), silencing the touchpad interrupt until the dGPU wakes
back up to D0. Under Windows, _DSW is not armed for S0 D3cold on this
root port, leaving WKEN = 0 so POFF() powers off the dGPU (\PIN.OFF(PWRG))
without touching GPP_A20.

_DSW on the root port is reached through two paths: acpi_pci_wakeup()
on the root port itself, and acpi_pci_propagate_wakeup() when the dGPU
below it runtime-suspends. Both only check acpi_pm_device_can_wakeup(),
i.e. adev->wakeup.flags.valid, so clearing the device's wakeup
capability is not enough (the PCIe PME service sets it again anyway).

Add an early PCI fixup in drivers/acpi/x86/utils.c for boards MS-1592
and MS-1594 on root port 0000:00:06.0 (8086:464d on 12th Gen Alder
Lake-P and 8086:a74d on 13th Gen Raptor Lake-P/H) that clears
adev->wakeup.flags.valid on its ACPI companion. Early fixups run from
pci_setup_device() after pci_set_acpi_fwnode() and before
pci_device_add() calls device_add(), so pci_acpi_setup() never sees the
port as ACPI wakeup capable and stays balanced with pci_acpi_cleanup().
The root port and dGPU still reach D3cold normally, while GPP_A20 stays
owned by the GPIO driver.

Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220725
Cc: stable@vger.kernel.org
Signed-off-by: Victor Carreras <vicajilau@gmail.com>
---
Changes in v3:
- Clear adev->wakeup.flags.valid from a DECLARE_PCI_FIXUP_EARLY quirk
  instead of clearing the device wakeup flags in a final fixup. In v2,
  pcie_pme_mark_devices() set can_wakeup back to true, and
  acpi_pci_wakeup() / acpi_pci_propagate_wakeup() only check
  adev->wakeup.flags.valid, so _DSW was still evaluated (sashiko-bot).
  Running before pci_acpi_setup() keeps setup and cleanup balanced.
- Tested on MS-1594 without the SSDT override: PEG0 no longer shows up
  in /proc/acpi/wakeup, the root port and dGPU reach D3cold and the
  touchpad keeps generating interrupts across repeated D3cold cycles.
- Link to v2: https://lore.kernel.org/r/20261024054711.21587-1-vicajilau@gmail.com

Changes in v2:
- Move the quirk from drivers/pci/quirks.c to drivers/acpi/x86/utils.c
  as it is x86-specific (Lukas Wunner).
- Link to v1: https://lore.kernel.org/r/179272791966.20251.3697951431087014523@gmail.com

 drivers/acpi/x86/utils.c | 53 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/drivers/acpi/x86/utils.c b/drivers/acpi/x86/utils.c
index 418951639..11a5d51be 100644
--- a/drivers/acpi/x86/utils.c
+++ b/drivers/acpi/x86/utils.c
@@ -665,3 +665,56 @@ void __init acpi_proc_quirk_mwait_check(void)
 	 */
 	dmi_check_system(acpi_proc_quirk_mwait_dmi_table);
 }
+
+/*
+ * On MSI Summit E16 Flip A12UCT (board MS-1592) and MSI Prestige 16 Studio
+ * A13VE / Summit E16 Flip A13VET (board MS-1594), the BIOS SSDT (MSI_NB /
+ * AdlP_Rvp) assigns the touchpad's GPIO interrupt pin (GPP_A20) as the PCIe
+ * wake GPIO (WAKG / P1WP) for the dGPU root port (\_SB.PC00.PEG0, 0000:00:06.0).
+ *
+ * When ACPI wakeup is armed on this root port via _DSW (setting WKEN = 1),
+ * subsequent D3cold transitions (\_SB.PC00.PEG0.PXP._OFF -> POFF) call
+ * \_SB.SHPO(WAKG, Zero), switching GPP_A20 ownership from GPIO driver mode
+ * to ACPI GPE mode and freezing the I2C touchpad (ELAN0305:00).
+ *
+ * Mark the root port's ACPI wakeup as invalid so that _DSW is never evaluated
+ * for it, neither directly nor when wakeup is propagated from the dGPU below
+ * it. This has to happen before pci_acpi_setup() runs from device_add(), so
+ * that pci_acpi_setup() and pci_acpi_cleanup() see the same state.
+ */
+static const struct dmi_system_id msi_peg0_no_wakeup_dmi_table[] = {
+	{
+		.ident = "MSI MS-1592",
+		.matches = {
+			DMI_MATCH(DMI_BOARD_VENDOR, "Micro-Star International Co., Ltd."),
+			DMI_MATCH(DMI_BOARD_NAME, "MS-1592"),
+		},
+	},
+	{
+		.ident = "MSI MS-1594",
+		.matches = {
+			DMI_MATCH(DMI_BOARD_VENDOR, "Micro-Star International Co., Ltd."),
+			DMI_MATCH(DMI_BOARD_NAME, "MS-1594"),
+		},
+	},
+	{}
+};
+
+static void quirk_msi_peg0_no_wakeup(struct pci_dev *dev)
+{
+	struct acpi_device *adev = ACPI_COMPANION(&dev->dev);
+
+	if (!adev || !adev->wakeup.flags.valid)
+		return;
+
+	if (pci_dev_id(dev) != PCI_DEVID(0, PCI_DEVFN(6, 0)))
+		return;
+
+	if (!dmi_check_system(msi_peg0_no_wakeup_dmi_table))
+		return;
+
+	pci_info(dev, FW_BUG "Disabling ACPI wakeup to avoid touchpad GPIO (GPP_A20) takeover in D3cold\n");
+	adev->wakeup.flags.valid = 0;
+}
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x464d, quirk_msi_peg0_no_wakeup);
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0xa74d, quirk_msi_peg0_no_wakeup);
-- 
2.55.0