[PATCH 1/3][SRU][Unstable/OEM-5.17] UBUNTU: SAUCE: PCI/ASPM: Enable ASPM for links under VMD domain

[You-Sheng Yang]

From: Kai-Heng Feng <kai.heng.feng at canonical.com>

BugLink: https://bugs.launchpad.net/bugs/1942160

New Intel laptops with VMD cannot reach deeper power saving state,
renders very short battery time.

As BIOS may not be able to program the config space for devices under
VMD domain, ASPM needs to be programmed manually by software. This is
also the case under Windows.

The VMD controller itself is a root complex integrated endpoint that
doesn't have ASPM capability, so we can't propagate the ASPM settings to
devices under it. Hence, simply apply ASPM_STATE_ALL to the links under
VMD domain, unsupported states will be cleared out anyway.

Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
---
 drivers/pci/pcie/aspm.c |  3 ++-
 drivers/pci/quirks.c    | 12 ++++++++++++
 include/linux/pci.h     |  2 ++
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 83216c19f5bd0..46ecdb1c1ce40 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -657,7 +657,8 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
 		aspm_calc_l1ss_info(link, parent_l1ss_cap, child_l1ss_cap);
 
 	/* Save default state */
-	link->aspm_default = link->aspm_enabled;
+	link->aspm_default = parent->dev_flags & PCI_DEV_FLAGS_ENABLE_ASPM ?
+			     ASPM_STATE_ALL : link->aspm_enabled;
 
 	/* Setup initial capable state. Will be updated later */
 	link->aspm_capable = link->aspm_support;
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index cbdfb5024e003..d4ef2a06d5548 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -5931,3 +5931,15 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x15f9, pci_fixup_serialize_tgl_me_
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x15fa, pci_fixup_serialize_tgl_me_pm);
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x15f4, pci_fixup_serialize_tgl_me_pm);
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x15f5, pci_fixup_serialize_tgl_me_pm);
+
+/*
+ * Device [8086:9a09]
+ * BIOS may not be able to access config space of devices under VMD domain, so
+ * it relies on software to enable ASPM for links under VMD.
+ */
+static void pci_fixup_enable_aspm(struct pci_dev *pdev)
+{
+	pdev->dev_flags |= PCI_DEV_FLAGS_ENABLE_ASPM;
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9a09, pci_fixup_enable_aspm);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0xa0b0, pci_fixup_enable_aspm);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 8392a78a1f1bf..33246c4e39c39 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -244,6 +244,8 @@ enum pci_dev_flags {
 	PCI_DEV_FLAGS_NO_RELAXED_ORDERING = (__force pci_dev_flags_t) (1 << 11),
 	/* Device does honor MSI masking despite saying otherwise */
 	PCI_DEV_FLAGS_HAS_MSI_MASKING = (__force pci_dev_flags_t) (1 << 12),
+	/* Enable ASPM regardless of how LnkCtl is programmed */
+	PCI_DEV_FLAGS_ENABLE_ASPM = (__force pci_dev_flags_t) (1 << 13),
 };
 
 enum pci_irq_reroute_variant {
-- 
2.34.1