From 907a7a2e5bf40c6a359b2f6cc53d6fdca04009e0 Mon Sep 17 00:00:00 2001 From: Mario Limonciello Date: Wed, 11 Jun 2025 18:31:16 -0500 Subject: [PATCH 1/2] PCI/PM: Set up runtime PM even for devices without PCI PM 4d4c10f763d7 ("PCI: Explicitly put devices into D0 when initializing") intended to put PCI devices into D0, but in doing so unintentionally changed runtime PM initialization not to occur on devices that don't support PCI PM. This caused a regression in vfio-pci due to an imbalance with its use. Adjust the logic in pci_pm_init() so that even if PCI PM isn't supported runtime PM is still initialized. Fixes: 4d4c10f763d7 ("PCI: Explicitly put devices into D0 when initializing") Reported-by: Giovanni Cabiddu Closes: https://lore.kernel.org/linux-pci/20250424043232.1848107-1-superm1@kernel.org/T/#m7e8929d6421690dc8bd6dc639d86c2b4db27cbc4 Reported-by: Nicolas Dichtel Closes: https://lore.kernel.org/linux-pci/20250424043232.1848107-1-superm1@kernel.org/T/#m40d277dcdb9be64a1609a82412d1aa906263e201 Signed-off-by: Mario Limonciello Signed-off-by: Bjorn Helgaas Tested-by: Giovanni Cabiddu Tested-by: Nicolas Dichtel Reviewed-by: Kuppuswamy Sathyanarayanan Acked-by: Rafael J. Wysocki Cc: Alex Williamson Link: https://patch.msgid.link/20250611233117.61810-1-superm1@kernel.org --- drivers/pci/pci.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index e9448d55113b..9e42090fb108 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -3217,14 +3217,14 @@ void pci_pm_init(struct pci_dev *dev) /* find PCI PM capability in list */ pm = pci_find_capability(dev, PCI_CAP_ID_PM); if (!pm) - return; + goto poweron; /* Check device's ability to generate PME# */ pci_read_config_word(dev, pm + PCI_PM_PMC, &pmc); if ((pmc & PCI_PM_CAP_VER_MASK) > 3) { pci_err(dev, "unsupported PM cap regs version (%u)\n", pmc & PCI_PM_CAP_VER_MASK); - return; + goto poweron; } dev->pm_cap = pm; @@ -3269,6 +3269,7 @@ void pci_pm_init(struct pci_dev *dev) pci_read_config_word(dev, PCI_STATUS, &status); if (status & PCI_STATUS_IMM_READY) dev->imm_ready = 1; +poweron: pci_pm_power_up_and_verify_state(dev); pm_runtime_forbid(&dev->dev); pm_runtime_set_active(&dev->dev); From bbf10cd686835d5a4b8566dc73a3b00b4cd7932a Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Wed, 18 Jun 2025 16:38:25 +0200 Subject: [PATCH 2/2] PCI: pciehp: Ignore belated Presence Detect Changed caused by DPC MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Commit c3be50f7547c ("PCI: pciehp: Ignore Presence Detect Changed caused by DPC") sought to ignore Presence Detect Changed events occurring as a side effect of Downstream Port Containment. The commit awaits recovery from DPC and then clears events which occurred in the meantime. However if the first event seen after DPC is Data Link Layer State Changed, only that event is cleared and not Presence Detect Changed. The object of the commit is thus defeated. That's because pciehp_ist() computes the events to clear based on the local "events" variable instead of "ctrl->pending_events". The former contains the events that had occurred when pciehp_ist() was entered, whereas the latter also contains events that have accumulated while awaiting DPC recovery. In practice, the order of PDC and DLLSC events is arbitrary and the delay in-between can be several milliseconds. So change the logic to always clear PDC events, even if they come after an initial DLLSC event. Fixes: c3be50f7547c ("PCI: pciehp: Ignore Presence Detect Changed caused by DPC") Reported-by: Lương Việt Hoàng Reported-by: Joel Mathew Thomas Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219765#c165 Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Tested-by: Lương Việt Hoàng Tested-by: Joel Mathew Thomas Link: https://patch.msgid.link/d9c4286a16253af7e93eaf12e076e3ef3546367a.1750257164.git.lukas@wunner.de --- drivers/pci/hotplug/pciehp_hpc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index ebd342bda235..91d2d92717d9 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -771,7 +771,7 @@ static irqreturn_t pciehp_ist(int irq, void *dev_id) u16 ignored_events = PCI_EXP_SLTSTA_DLLSC; if (!ctrl->inband_presence_disabled) - ignored_events |= events & PCI_EXP_SLTSTA_PDC; + ignored_events |= PCI_EXP_SLTSTA_PDC; events &= ~ignored_events; pciehp_ignore_link_change(ctrl, pdev, irq, ignored_events);