linux/drivers/pci, branch v6.7

Merge tag 'pci-v6.7-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci

2024-01-03T22:18:57Z

Pull PCI fixes from Bjorn Helgaas: - Revert an ASPM patch that caused an unintended reboot when resuming after suspend (Bjorn Helgaas) - Orphan Cadence PCIe IP (Bjorn Helgaas) * tag 'pci-v6.7-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci: MAINTAINERS: Orphan Cadence PCIe IP Revert "PCI/ASPM: Remove pcie_aspm_pm_state_change()"

Revert "PCI/ASPM: Remove pcie_aspm_pm_state_change()"

2024-01-02T23:29:15Z

This reverts commit 08d0cc5f34265d1a1e3031f319f594bd1970976c. Michael reported that when attempting to resume from suspend to RAM on ASUS mini PC PN51-BB757MDE1 (DMI model: MINIPC PN51-E1), 08d0cc5f3426 ("PCI/ASPM: Remove pcie_aspm_pm_state_change()") caused a 12-second delay with no output, followed by a reboot. Workarounds include: - Reverting 08d0cc5f3426 ("PCI/ASPM: Remove pcie_aspm_pm_state_change()") - Booting with "pcie_aspm=off" - Booting with "pcie_aspm.policy=performance" - "echo 0 | sudo tee /sys/bus/pci/devices/0000:03:00.0/link/l1_aspm" before suspending - Connecting a USB flash drive Link: https://lore.kernel.org/r/20240102232550.1751655-1-helgaas@kernel.org Fixes: 08d0cc5f3426 ("PCI/ASPM: Remove pcie_aspm_pm_state_change()") Reported-by: Michael Schaller Link: https://lore.kernel.org/r/76c61361-b8b4-435f-a9f1-32b716763d62@5challer.de Signed-off-by: Bjorn Helgaas Cc:

Revert "PCI: acpiphp: Reassign resources on bridge if necessary"

2023-12-15T20:55:10Z

This reverts commit 40613da52b13fb21c5566f10b287e0ca8c12c4e9 and the subsequent fix to it: cc22522fd55e ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus") 40613da52b13 fixed a problem where hot-adding a device with large BARs failed if the bridge windows programmed by firmware were not large enough. cc22522fd55e ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus") fixed a problem with 40613da52b13: an ACPI hot-add of a device on a PCI root bus (common in the virt world) or firmware sending ACPI Bus Check to non-existent Root Ports (e.g., on Dell Inspiron 7352/0W6WV0) caused a NULL pointer dereference and suspend/resume hangs. Unfortunately the combination of 40613da52b13 and cc22522fd55e caused other problems: - Fiona reported that hot-add of SCSI disks in QEMU virtual machine fails sometimes. - Dongli reported a similar problem with hot-add of SCSI disks. - Jonathan reported a console freeze during boot on bare metal due to an error in radeon GPU initialization. Revert both patches to avoid adding these problems. This means we will again see the problems with hot-adding devices with large BARs and the NULL pointer dereferences and suspend/resume issues that 40613da52b13 and cc22522fd55e were intended to fix. Fixes: 40613da52b13 ("PCI: acpiphp: Reassign resources on bridge if necessary") Fixes: cc22522fd55e ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus") Reported-by: Fiona Ebner Closes: https://lore.kernel.org/r/9eb669c0-d8f2-431d-a700-6da13053ae54@proxmox.com Reported-by: Dongli Zhang Closes: https://lore.kernel.org/r/3c4a446a-b167-11b8-f36f-d3c1b49b42e9@oracle.com Reported-by: Jonathan Woithe Closes: https://lore.kernel.org/r/ZXpaNCLiDM+Kv38H@marvin.atrad.com.au Signed-off-by: Bjorn Helgaas Acked-by: Michael S. Tsirkin Acked-by: Igor Mammedov Cc:

PCI/ASPM: Add pci_disable_link_state_locked() lockdep assert

2023-12-11T18:09:23Z

Add a lockdep assert to pci_disable_link_state_locked() which should only be called with a pci_bus_sem read lock held. Link: https://lore.kernel.org/r/20231128081512.19387-7-johan+linaro@kernel.org Signed-off-by: Johan Hovold [bhelgaas: include function name in subject, commit log] Signed-off-by: Bjorn Helgaas Reviewed-by: Manivannan Sadhasivam

PCI/ASPM: Clean up __pci_disable_link_state() 'sem' parameter

2023-12-11T18:08:55Z

Replace the current 'sem' parameter to the __pci_disable_link_state() helper with a more descriptive 'locked' parameter, which indicates whether a pci_bus_sem read lock is already held. Link: https://lore.kernel.org/r/20231128081512.19387-6-johan+linaro@kernel.org Signed-off-by: Johan Hovold [bhelgaas: include function name in subject, commit log] Signed-off-by: Bjorn Helgaas Reviewed-by: Manivannan Sadhasivam

PCI: qcom: Clean up ASPM comment

2023-12-11T18:08:53Z

Break up the newly added ASPM comment so that it fits within the soft 80 character limit and becomes more readable. Link: https://lore.kernel.org/r/20231128081512.19387-5-johan+linaro@kernel.org Signed-off-by: Johan Hovold Signed-off-by: Bjorn Helgaas

PCI: qcom: Fix potential deadlock when enabling ASPM

2023-12-11T18:08:43Z

The qcom_pcie_enable_aspm() helper is called from pci_walk_bus() during host init to enable ASPM. Since pci_walk_bus() already holds a pci_bus_sem read lock, use pci_enable_link_state_locked() to enable link states in order to avoid a potential deadlock (e.g. in case someone takes a write lock before reacquiring the read lock). This issue was reported by lockdep: ============================================ WARNING: possible recursive locking detected 6.7.0-rc1 #4 Not tainted -------------------------------------------- kworker/u16:6/147 is trying to acquire lock: ffffbf3ff9d2cfa0 (pci_bus_sem){++++}-{3:3}, at: pci_enable_link_state+0x74/0x1e8 but task is already holding lock: ffffbf3ff9d2cfa0 (pci_bus_sem){++++}-{3:3}, at: pci_walk_bus+0x34/0xbc other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(pci_bus_sem); lock(pci_bus_sem); *** DEADLOCK *** Fixes: 9f4f3dfad8cf ("PCI: qcom: Enable ASPM for platforms supporting 1.9.0 ops") Link: https://lore.kernel.org/r/20231128081512.19387-4-johan+linaro@kernel.org Signed-off-by: Johan Hovold [bhelgaas: add "potential" in subject since the deadlock has only been reported by lockdep, include helper name in commit log] Signed-off-by: Bjorn Helgaas Reviewed-by: Manivannan Sadhasivam

PCI: vmd: Fix potential deadlock when enabling ASPM

2023-12-11T18:07:59Z

The vmd_pm_enable_quirk() helper is called from pci_walk_bus() during probe to enable ASPM for controllers with VMD_FEAT_BIOS_PM_QUIRK set. Since pci_walk_bus() already holds a pci_bus_sem read lock, use pci_enable_link_state_locked() to enable link states in order to avoid a potential deadlock (e.g. in case someone takes a write lock before reacquiring the read lock). Fixes: f492edb40b54 ("PCI: vmd: Add quirk to configure PCIe ASPM and LTR") Link: https://lore.kernel.org/r/20231128081512.19387-3-johan+linaro@kernel.org Signed-off-by: Johan Hovold [bhelgaas: add "potential" in subject since the deadlock has only been reported by lockdep, include helper name in commit log] Signed-off-by: Bjorn Helgaas Reviewed-by: Manivannan Sadhasivam Cc: # 6.3 Cc: Michael Bottini Cc: David E. Box

PCI/ASPM: Add pci_enable_link_state_locked()

2023-12-11T18:07:42Z

Add pci_enable_link_state_locked() for enabling link states that can be used in contexts where a pci_bus_sem read lock is already held (e.g. from pci_walk_bus()). This helper will be used to fix a couple of potential deadlocks where the current helper is called with the lock already held, hence the CC stable tag. Fixes: f492edb40b54 ("PCI: vmd: Add quirk to configure PCIe ASPM and LTR") Link: https://lore.kernel.org/r/20231128081512.19387-2-johan+linaro@kernel.org Signed-off-by: Johan Hovold [bhelgaas: include helper name in subject, commit log] Signed-off-by: Bjorn Helgaas Reviewed-by: Manivannan Sadhasivam Cc: # 6.3 Cc: Michael Bottini Cc: David E. Box

PCI: loongson: Limit MRRS to 256

2023-12-08T16:48:37Z

This is a partial revert of 8b3517f88ff2 ("PCI: loongson: Prevent LS7A MRRS increases") for MIPS-based Loongson. Some MIPS Loongson systems don't support arbitrary Max_Read_Request_Size (MRRS) settings. 8b3517f88ff2 ("PCI: loongson: Prevent LS7A MRRS increases") worked around that by (1) assuming that firmware configured MRRS to the maximum supported value and (2) preventing the PCI core from increasing MRRS. Unfortunately, some firmware doesn't set that maximum MRRS correctly, which results in devices not being initialized correctly. One symptom, from the Debian report below, is this: ata4.00: exception Emask 0x0 SAct 0x20000000 SErr 0x0 action 0x6 frozen ata4.00: failed command: WRITE FPDMA QUEUED ata4.00: cmd 61/20:e8:00:f0:e1/00:00:00:00:00/40 tag 29 ncq dma 16384 out res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout) ata4.00: status: { DRDY } ata4: hard resetting link Limit MRRS to 256 because MIPS Loongson with higher MRRS support is considered rare. This must be done at device enablement stage because the MRRS setting may get lost if PCI_COMMAND_MASTER on the parent bridge is cleared, and we are only sure parent bridge is enabled at this point. Fixes: 8b3517f88ff2 ("PCI: loongson: Prevent LS7A MRRS increases") Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217680 Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1035587 Link: https://lore.kernel.org/r/20231201115028.84351-1-jiaxun.yang@flygoat.com Signed-off-by: Jiaxun Yang Signed-off-by: Bjorn Helgaas Acked-by: Huacai Chen Cc: stable@vger.kernel.org