Subject: Re: [REGRESSION 00/04] Crash during resume of pcie bridge

From: Bert Karwatzki <[email-masked]>
Date: Fri, 31 Oct 2025 14:47:20 +0100

Upon closer inspection I noticed that the PCIe bandwitdth has been reduced:

> 
> [76621.870884] [    T140] pcieport 0000:01:00.0: Unable to change power state from D3cold to D0, device inaccessible
> [76621.870977] [    T140] pcieport 0000:02:00.0: Unable to change power state from D3cold to D0, device inaccessible
> [76621.876006] [    T140] pci_bus 0000:03: busn_res: [bus 03] is released
> [76621.878237] [    T140] pci_bus 0000:02: busn_res: [bus 02-03] is released
> [76621.879867] [    T140] pcieport 0000:00:01.1: pciehp: Slot(0): Card present
> [76621.879873] [    T140] pcieport 0000:00:01.1: pciehp: Slot(0): Link Up
> [76622.006565] [    T140] pci 0000:01:00.0: [1002:1478] type 01 class 0x060400 PCIe Switch Upstream Port
> [76622.006606] [    T140] pci 0000:01:00.0: BAR 0 [mem 0xfcc00000-0xfcc03fff]
> [76622.006616] [    T140] pci 0000:01:00.0: PCI bridge to [bus 02-03]
> [76622.006630] [    T140] pci 0000:01:00.0:   bridge window [mem 0xfca00000-0xfcbfffff]
> [76622.006644] [    T140] pci 0000:01:00.0:   bridge window [mem 0xfc00000000-0xfe0fffffff 64bit pref]
> [76622.006772] [    T140] pci 0000:01:00.0: PME# supported from D0 D3hot D3cold

The PCIe band with seems to be have been reduce to PCIe 1.0 (2.5GT/s):

> [76622.006874] [    T140] pci 0000:01:00.0: 16.000 Gb/s available PCIe bandwidth, limited by 2.5 GT/s PCIe x8 link at 0000:00:01.1 (capable of 126.024 Gb/s with
> 16.0 GT/s PCIe x8 link)
> 
> Bert Karwatzki

This is the same message from system startup (here it's PCIe 3.0 (8.0GT/s), which is the PCIe version
of the CPU (AMD Ryzen 7 5800H with Radeon Graphics)):	
[    0.289221] [      T1] pci 0000:01:00.0: 63.008 Gb/s available PCIe bandwidth, limited by 8.0 GT/s PCIe x8 link at 0000:00:01.1 (capable of 126.024 Gb/s with
16.0 GT/s PCIe x8 link)

Bert Karwatzki