[PATCH] PCI: Disable spurious s2idle wake from the NVMe root port on ThinkPad P1 Gen 9

[Kean Ren <rh_king@163.com>]

On Lenovo ThinkPad P1 Gen 9 (21UF, Panther Lake), firmware enables the
ACPI wake capability (_PRW) of PCIe root port 00:1c.4, which is the root
port of the primary NVMe SSD.  When the NVMe controller is put into D3
during system suspend, a spurious PME is raised on that root port, which
sets ACPI GPE 0x6F (SCI).  The SCI fires during the noirq suspend phase
and aborts s2idle before it reaches the low-power state: every suspend
is followed by a wake within ~2.5 seconds with practically zero s2idle
residency.

The downstream NVMe device is not a wake source (its own ACPI wake is
disabled), so the spurious event comes from the root port's wake/PME
path.  Disable the root port's wake capability as well.

No firmware with a fix is available: the issue reproduces with BIOS
N4SET31W (1.10) and N4SET32W (1.11), the latest version at the time of
writing.  Match the model only; if a fixed BIOS is released later, this
quirk can be removed or restricted to the affected BIOS versions.

Verified on 21UFZE0PCN:
 - gpe6F increments by one per suspend/resume on both BIOS versions;
 - masking gpe6F, or disabling RP05 wake via /proc/acpi/wakeup, makes
   s2idle stay asleep;
 - with this quirk, /proc/acpi/wakeup reports RP05 as disabled and
   gpe6F no longer increments across repeated suspends.

Signed-off-by: Kean Ren <rh_king@163.com>
---
 drivers/pci/quirks.c | 52 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 7f1f47ea2ee4..daccfbbec821 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -6595,3 +6595,55 @@ static void pci_mask_replay_timer_timeout(struct pci_dev *pdev)
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_GLI, 0x9750, pci_mask_replay_timer_timeout);
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_GLI, 0x9755, pci_mask_replay_timer_timeout);
 #endif
+
+/*
+ * Lenovo ThinkPad P1 Gen 9 (21UF): the firmware enables the ACPI wake
+ * capability of PCIe root port 00:1c.4, which is the root port of the
+ * primary NVMe SSD.  When the NVMe controller is put into D3 during
+ * system suspend, a spurious PME is raised on that root port, which in
+ * turn fires ACPI GPE 0x6F (SCI) and aborts s2idle before the system
+ * reaches the low-power state.  The NVMe device itself is not a wake
+ * source (its own ACPI wake is disabled), so disable the root port's
+ * wake capability as well.
+ *
+ * No firmware with a fix is available: the issue reproduces with BIOS
+ * N4SET31W (1.10) and N4SET32W (1.11), the latest version at the time
+ * of writing.  Match the model only; if a fixed BIOS is released later,
+ * this quirk can be removed or restricted to the affected BIOS
+ * versions.
+ */
+static const struct dmi_system_id p1g9_rp05_wakeup_dmi[] __initconst = {
+	{
+		.ident = "Lenovo ThinkPad P1 Gen 9 (21UF)",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "21UFZE0PCN"),
+		},
+	},
+	{ }
+};
+
+static int __init pci_fixup_p1g9_rp05_wakeup(void)
+{
+	struct pci_dev *rp;
+
+	if (!dmi_check_system(p1g9_rp05_wakeup_dmi))
+		return 0;
+
+	/* Root port of the primary NVMe SSD (05:00.0). */
+	rp = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(0x1c, 4));
+	if (!rp)
+		return 0;
+
+	if (device_can_wakeup(&rp->dev)) {
+		device_set_wakeup_enable(&rp->dev, false);
+		pci_info(rp, "disabled spurious s2idle wake (BIOS %s)\n",
+			 dmi_get_system_info(DMI_BIOS_VERSION));
+	} else {
+		pci_warn(rp, "wakeup not enabled, cannot disable spurious s2idle wake\n");
+	}
+	pci_dev_put(rp);
+
+	return 0;
+}
+late_initcall(pci_fixup_p1g9_rp05_wakeup);
-- 
2.43.0