[BUG] ath10k_pci: QCA9377 reports recurring PCIe AER RxErr/BadDLLP errors with ASPM enabled

[Rakesh]

Hello,

I am reporting what appears to be a reproducible ASPM-related issue
affecting the Qualcomm Atheros QCA9377 (ath10k_pci) wireless adapter.

I initially reported this to the PCI subsystem in Kernel Bugzilla:

https://bugzilla.kernel.org/show_bug.cgi?id=221784

The report was reviewed, and I was advised to report it to the
ath10k/linux-wireless maintainers since the PCI subsystem itself
appears to be functioning correctly.

Hardware:

Dell Latitude 3500
BIOS 1.37.0
Intel PCIe Root Port: 8086:9db1
Qualcomm Atheros QCA9377 (168c:0042), subsystem 1028:1810
Driver: ath10k_pci

Kernels tested:

Ubuntu 20.04 (Linux 5.15.x)
Ubuntu development release (Linux 7.0.0-14)

Observed behavior:
With ASPM enabled, the system continuously reports PCIe AER
Correctable Errors, primarily RxErr and BadDLLP, while the wireless
device is active. The issue is consistently reproducible.

Workaround:
Booting with:

pcie_aspm=off

completely eliminates the AER errors.

Additional observations:

ASPM L1 is enabled on the PCIe link.
L1.1/L1.2 substates are enabled on both the Root Port and the endpoint.
During initialization, ath10k_pci temporarily disables ASPM and later
restores it.
I was unable to find an existing device-specific ASPM/AER quirk for the QCA9377.

The Bugzilla report contains the complete investigation, hardware
information, lspci output, dmesg logs, and supporting diagnostics:

https://bugzilla.kernel.org/show_bug.cgi?id=221784

If additional diagnostics, testing, or patches would be helpful, I
would be happy to assist.

Thank you for your time.

Best regards,

Alasyam Rakesh