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Question

the kernel is unable to assign the 32MB BAR 2 region due to space limitations ( code: can't assign; no space

  • September 14, 2026
  • 0 replies
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 I am using the Axelera Embedded 110m module (Metis AIPU) on a NanoPC-T6 Plus board.Please note that I am using the NanoPC-T6 Plus (LPDDR5 architecture), not the standard NanoPC-T6 (LPDDR4X). The official image provided for the standard NanoPC-T6 does not resolve the PCIe memory allocation failure (

code:

error -12

) on the T6 Plus due to hardware and Device Tree differences between the two boards.I have tested the official Ubuntu 22.04 and Ubuntu 24.04 OS images provided on the official NanoPC-T6 Plus wiki page, as well as the Armbian 26.8.3 NanoPC LTS image, but the issue persists on all of them.Here are the troubleshooting steps I have attempted so far:

  1. Added the recommended kernel parameters (scode]pci=realloc=on[/code] and ncode]pcie_aspm=off[/code]) to the boot configuration.
  2. Decompiled and manually updated the hcode]ranges[/code] property in the Device Tree (ecode].dtb[/code]) to expand the non-prefetchable MMIO window for the PCIe controller node.
  3. Performed a full cold power cycle (completely disconnecting the power cable) after each attempt.

Unfortunately, the kernel is still unable to assign the 32MB BAR 2 region due to space limitations (

code:

can't assign; no space

):

  1. [code]cat /proc/cmdline[/code]: Confirms mcode]pci=realloc=on pcie_aspm=off[/code] is active.
  2. [code]sudo dmesg | grep -iE 'axl|pcie|0000:01:00.0'[/code]:bcode]pci 0000:01:00.0: BAR 2 mem size 0x02000000]: can't assign; no space pci 0000:01:00.0: BAR 0 mem size 0x00001000 64bit]: can't assign; no space axl 0000:01:00.0: Failed to request resources axl 0000:01:00.0: probe with driver axl failed with error -12 [/code]
  3. [code]axdevice[/code]: Still reports tcode]WARNING: PCI device count mismatch: lspci=1, triton=0[/code].

Do you have an officially verified OS image or a pre-patched

code:

.dtb

file specifically configured for the NanoPC-T6 Plus to support the Embedded 110m module?Thank you for your support!