OpenWrt 24.10 x86-64 Boot Hangs After PCI/NVMe Initialization

[a.seregin]

Issue Description:
When booting OpenWrt 24.10 x86-64 (kernel 6.6.83), the system stops after PCI and ACPI initialization without mounting the root filesystem. The log shows no errors but also lacks messages like VFS: Mounting root.
Openwrt 23.05 works correctly.

Configuration:

• Hardware: PICO319, Intel Atom E3940
• Boot Parameters:

  root=PARTUUID=550e4248-2297-768a-f189-416b2dcb4102 rootwait debug console=tty1 console=ttyS0,115200n8r noinitrd 
  

Boot Log Highlights:

1. Kernel starts, detects CPU, memory, and PCI devices (including NVMe controller).
2. ACPI initializes, but all IRQ links are disabled:

   ACPI: PCI: Interrupt link LNKA disabled  
   ...  
   ACPI: PCI: Interrupt link LNKH disabled  
   

3. No messages about root FS mounting attempts or NVMe errors.

Booting OpenWrt log

https://pastebin.com/XwqN1AuJ

[steve84]

Looks like there are some patches related to this chipset for yocto here: https://github.com/ADLINK/meta-adlink-x86-64bit/blob/scarthgap/recipes-kernel/linux-intel/linux-intel/0001-Avoid-ACPI-probe-due-to-resource-conflict-with-BIOS.patch I've seen similar issues booting 24.10 kernels on an AD-LINK LEC-AL-E3940 which is the same Atom processor. I've also seen issues on the debian 6.12 / trixie kernel but not 6.1 / bookworm. Suggests the problem is not OpenWRT specific

[a.seregin]

Added this patch to package/kernel/linux/patches, but it didn't help.

[ikazuhiro]

My device needs CONFIG_PCI_MMCONFIG=y kernel configuration to boot on kernel 6.6, which was not needed on kernel 6.1. Please try following patch.

--- a/target/linux/x86/64/config-6.6
+++ b/target/linux/x86/64/config-6.6
@@ -345,6 +345,7 @@ CONFIG_MFD_CORE=y
 # CONFIG_MFD_INTEL_LPSS_ACPI is not set
 # CONFIG_MFD_INTEL_PMC_BXT is not set
 CONFIG_MMC=y
+CONFIG_MMCONF_FAM10H=y
 CONFIG_MMC_BLOCK=y
 CONFIG_MMC_CQHCI=y
 CONFIG_MMC_RICOH_MMC=y
@@ -404,7 +405,7 @@ CONFIG_PCIEPORTBUS=y
 CONFIG_PCIE_PME=y
 CONFIG_PCI_HYPERV=y
 CONFIG_PCI_HYPERV_INTERFACE=y
-# CONFIG_PCI_MMCONFIG is not set
+CONFIG_PCI_MMCONFIG=y
 CONFIG_PCI_PASID=y
 CONFIG_PCI_PRI=y
 CONFIG_PCI_XEN=y

[a.seregin]

The patch didn't work, but I made the changes manually and the board booted up. Thanks a lot!