I do see that:
----
[E0] 781 /usr/src/ubuntu-kernel> dmesg | fgrep -i aspm
[ 0.164233] ACPI FADT declares the system doesn't support PCIe ASPM,
so disable it
[ 0.579946] acpi PNP0A08:00: _OSC: OS supports [ExtendedConfig ASPM
ClockPM Segments MSI EDR HPX-Type3]
[ 0.587377] acpi PNP0A08:00: FADT indicates ASPM is unsupported,
using BIOS configuration
[ 1.309826] pci 10000:e0:06.0: enable ASPM for pci bridge behind vmd
[ 1.622705] pci 10000:e1:00.0: can't override BIOS ASPM; OS doesn't
have ASPM control
[110757.878494] pcieport 0000:00:07.0: ASPM: current common clock
configuration is inconsistent, reconfiguring
[171953.284616] pcieport 0000:00:07.0: ASPM: current common clock
configuration is inconsistent, reconfiguring
----
On 12/19/24 08:25, David E. Box wrote:
Hi Kenneth,
On Fri, 2024-12-13 at 17:02 -0600, Bjorn Helgaas wrote:
[cc->to: David, Nirmal]
On Fri, Dec 13, 2024 at 02:26:37PM -0800, Kenneth Crudup wrote:
OK, it looks like the effective change (that's not already contained in the
LTR SNOOP patches already in Linus' master (et al.)) comes from this line
from the Ubuntu commit 1a0102a0 ("UBUNTU: SAUCE: PCI/ASPM: Enable ASPM for
links under VMD domain"):
----
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 00143f5fb83a..d2ff44e7fbb1 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -688,7 +688,8 @@ static void pcie_aspm_cap_init(struct pcie_link_state
*link, int blacklist)
aspm_l1ss_init(link);
/* 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;
So I thought the "pci_enable_link_state(pdev, PCIE_LINK_STATE_ALL)" in
f492edb40b54 would effectively do the same thing:
https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/
lunar/commit/?id=1a0102a08f206149d9abd56c2b28877c878b5526
This is "UBUNTU: SAUCE: PCI/ASPM: Enable ASPM for links under VMD
domain", which adds "link->aspm_default = ASPM_STATE_ALL" for device
IDs 0x9a09 and 0xa0b0.
This looks like it should also be handled by upstream f492edb40b54
("PCI: vmd: Add quirk to configure PCIe ASPM and LTR") [1], which adds
"pci_enable_link_state(pdev, PCIE_LINK_STATE_ALL)".
But I guess it doesn't actually work. I'm hoping David or Nirmal can
figure out why it doesn't because it seems obvious that it's the
intent.
Is PCIe ASPM disabled? In the kernel log do you see:
"can't override BIOS ASPM; OS doesn't have ASPM control"
David
--
Kenneth R. Crudup / Sr. SW Engineer, Scott County Consulting, Orange
County CA
