Arch Linux

Aqualung

Member

Registered: 2025-09-07

Posts: 45

Thunderbolt PCIe lanes locked at Gen1 (2.5 GT/s) instead of Gen3/Gen4

Could anyone think of an Arch-specific reason why my laptop (LG Gram 17ZB90R, Raptor Lake-P, Thunderbolt 4) has its Thunderbolt PCIe lanes locked at Gen1 (2.5 GT/s) instead of Gen3/Gen4? I have been going crazy for the past few days tweaking all sorts of BIOS settings and Grub kernel parameters, to no avail.

Could anyone running Arch on the same hardware confirm this?

Here goes:

[dad@DadsGram Workspace]$  powerprofilesctl get
performance
[dad@DadsGram Workspace]$  sudo lspci -vvv -s 00:07.3 2>/dev/null | grep -E "LnkCap:|LnkSta:|LnkCap2:"
[sudo] password for dad:                
                LnkCap: Port #5, Speed 2.5GT/s, Width x4, ASPM L1, Exit Latency L1 <16us
                LnkSta: Speed 2.5GT/s, Width x4
                LnkCap2: Supported Link Speeds: 2.5GT/s, Crosslink- Retimer- 2Retimers- DRS-
[dad@DadsGram Workspace]$  grep "bandwidth" ~/Documents/full.log 2>/dev/null | grep -v "failed" | head -5 || journalctl -b | grep "bandwidth" | grep -v "failed" | head -5
Jan 17 17:02:22 DadsGram kernel: pci 0000:2e:00.0: 8.000 Gb/s available PCIe bandwidth, limited by 2.5 GT/s PCIe x4 link at 0000:00:07.3 (capable of 15.752 Gb/s with 8.0 GT/s PCIe x2 link)
Jan 17 17:02:22 DadsGram kernel: pci 0000:2f:00.0: 8.000 Gb/s available PCIe bandwidth, limited by 2.5 GT/s PCIe x4 link at 0000:00:07.3 (capable of 31.504 Gb/s with 8.0 GT/s PCIe x4 link)
Jan 17 17:02:28 DadsGram kernel: pci 0000:2e:00.0: 8.000 Gb/s available PCIe bandwidth, limited by 2.5 GT/s PCIe x4 link at 0000:00:07.3 (capable of 15.752 Gb/s with 8.0 GT/s PCIe x2 link)
Jan 17 17:02:28 DadsGram kernel: pci 0000:2f:00.0: 8.000 Gb/s available PCIe bandwidth, limited by 2.5 GT/s PCIe x4 link at 0000:00:07.3 (capable of 31.504 Gb/s with 8.0 GT/s PCIe x4 link)