From the logs and the code, the driver times out after 200ms waiting for the PCIe link to come up. We could extend that time but I doubt that's going to help given that when the link does come up it comes up fairly quickly, long before the timeout.
BAD: [ 0.361545] pci_bus 0000:01: supply vpcie12v not found, using dummy regulator [ 0.606763] brcm-pcie fd500000.pcie: link down GOOD: [ 0.347484] pci_bus 0000:01: supply vpcie12v not found, using dummy regulator [ 0.451325] brcm-pcie fd500000.pcie: clkreq-mode set to default [ 0.453464] brcm-pcie fd500000.pcie: link up, 5.0 GT/s PCIe x1 (SSC) It's possible that the driver violates the PCI spec. I need to dig through the reset sequence. There are also some settings that change the reset behavior that we could explore. Not sure if that helps or matters. Also, maybe it's possible to limit the link to 2.5 GT/s to check if that makes it more stable. Can you attach the output of `sudo lspci -vvv` for a good and a bad state to the bug? And what's the output of `sudo vcgencmd bootloader_config`? -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/2099935 Title: PCI initialization failure following kernel panic reboot on Raspberry Pi CM4 Status in linux package in Ubuntu: Invalid Status in linux-raspi package in Ubuntu: Triaged Bug description: Ubuntu Server 24.10 Linux ubuntu 6.11.0-1004-raspi #4-Ubuntu SMP PREEMPT_DYNAMIC Fri Sep 27 22:25:34 UTC 2024 aarch64 aarch64 aarch64 GNU/Linux We're seeing that following a kernel panic and reboot, the PCI fails to initialize correctly and associated devices (such as Wi-Fi card) are not available. Issue Description: • On the first boot, everything works correctly. • However, after a Kernel Panic, the device reboots, but PCIe does not reset or re-initialize properly. • When this happens: o The Wi-Fi card is not recognized. o The lspci command shows no PCI devices. o The dmesg log includes the message: [ 0.591441] brcm-pcie fd500000.pcie: link down • A soft reboot does not fix the issue. • The only way to recover is to completely remove and reconnect power (hard reboot). We have tried modifying /boot/firmware/config.txt and /boot/firmware/cmdline.txt, which has reduced but not fully resolved the issue. How to Reproduce The Problem: 1. Power up the hardware 2. Run ‘lspci’ – observe the result includes the PCI Bridge and Wi-Fi card 3. Trigger a kernel panic with the command ‘echo c | sudo tee /proc/sysrq-trigger’, causing a reboot 4. Run ‘lspci’ – observer the output is now empty The same issue does not occur on Raspberry Pi OS - it seems to be specific to Ubuntu. Any assistance/guidance on how to troubleshoot this would be much appreciated! To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2099935/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
