On Tue, Mar 04, 2025 at 01:35:14PM +0530, Naveen Kumar P wrote: > On Fri, Feb 28, 2025 at 9:31 PM Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > > > On Wed, Feb 26, 2025 at 06:28:33PM +0530, Naveen Kumar P wrote: > > > On Wed, Feb 26, 2025 at 2:08 AM Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > > > On Tue, Feb 25, 2025 at 06:46:02PM +0530, Naveen Kumar P wrote: > > > > > On Tue, Feb 25, 2025 at 1:24 AM Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > > > > > On Tue, Feb 25, 2025 at 12:29:00AM +0530, Naveen Kumar P wrote: > > > > > > > On Mon, Feb 24, 2025 at 11:03 PM Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > > > > > > > On Mon, Feb 24, 2025 at 05:45:35PM +0530, Naveen Kumar P wrote: > > > > > > > > > On Wed, Feb 19, 2025 at 10:36 PM Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > > > > > > > > > On Wed, Feb 19, 2025 at 05:52:47PM +0530, Naveen Kumar P wrote: > > > > > > > > > > > Hi all, > > > > > > > > > > > > > > > > > > > > > > I am writing to seek assistance with an issue we are > > > > > > > > > > > experiencing with a PCIe device (PLDA Device 5555) > > > > > > > > > > > connected through PCI Express Root Port 1 to the > > > > > > > > > > > host bridge. > > > > > > > > > > > > > > > > > > > > > > We have observed that after booting the system, the > > > > > > > > > > > Base Address Register (BAR0) memory of this device > > > > > > > > > > > gets reset to 0x0 after approximately one hour or > > > > > > > > > > > more (the timing is inconsistent). This was verified > > > > > > > > > > > using the lspci output and the setpci -s 01:00.0 > > > > > > > > > > > BASE_ADDRESS_0 command. > > > > > > > ... > > > > > I have downloaded the 6.13 kernel source and added additional debug > > > logs in hotplug_event(), then built the kernel. After that rebooted > > > with the new kernel using the following parameters: > > > BOOT_IMAGE=/vmlinuz-6.13.0+ root=/dev/mapper/vg00-rootvol ro quiet > > > libata.force=noncq pci=nomsi pcie_aspm=off pcie_ports=on "dyndbg=file > > > drivers/pci/* +p; file drivers/acpi/* +p" > > > > Why "pci=nomsi"? I don't think that should make a difference. Also, > > it contributes to the fact that Linux doesn't request OS control of > > several features that it ordinarily does, so you end up in a somewhat > > unusual state (which *should* still work, of course): > > > > acpi PNP0A08:00: _OSC: OS supports [ExtendedConfig Segments HPX-Type3] > > acpi PNP0A08:00: _OSC: not requesting OS control; OS requires [ExtendedConfig ASPM ClockPM MSI] > > > > Same for "pcie_aspm=off". > > I initially suspected that the PCI BAR reset was happening due to the > device entering a low-power state, so I set pcie_aspm=off to prevent > it. ASPM never makes a device lose its state. It's completely invisible from a software point of view. > As per your suggestion, I instrumented the PCI configuration > accessors to log all reads and writes to my device (01:00.0). The > corresponding patch > (0002-instrumented-the-PCI-config-accessors-to-log-all-the.patch) is > attached to this email. After applying the patch and rebooting with > the same boot parameters, the issue reproduced after 193890 seconds. > > The complete dmesg log (dmesg_march3rd_log.txt) is also attached. > Could you check if this new log provides any useful clues? > [193890.407810] ACPI: \_SB_.PCI0.RP01: ACPI: ACPI_NOTIFY_BUS_CHECK event > [193890.407973] ACPI: \_SB_.PCI0.RP01: acpiphp_glue: Bridge acquired in hotplug_event() > [193890.408010] ACPI: \_SB_.PCI0.RP01: acpiphp_glue: Bus check in hotplug_event() > [193890.408030] ACPI: \_SB_.PCI0.RP01: acpiphp_glue: Checking bridge in hotplug_event() > [193890.408052] PCI READ: res=0, bus=01 dev=00 func=0 pos=0x00 len=4 data=0x55551556 > [193890.408095] PCI READ: res=0, bus=01 dev=00 func=0 pos=0x00 len=4 data=0x55551556 Looks perfectly fine. This is reading the Vendor and Device IDs. > [193890.408122] ACPI: \_SB_.PCI0.RP01: acpiphp_glue: Enabling slot in acpiphp_check_bridge() > [193890.408184] ACPI: Device [PXSX] status [0000000f] > [193890.408236] ACPI: Device [D015] status [0000000f] > [193890.408305] ACPI: \_SB_.PCI0.RP01: acpiphp_glue: Releasing bridge in hotplug_event()
