From 8ef0217227b42e2c34a18de316cee3da16c9bf1e Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Sun, 15 Jan 2023 09:20:31 +0100 Subject: [PATCH] PCI/PM: Observe reset delay irrespective of bridge_d3 If a PCI bridge is suspended to D3cold upon entering system sleep, resuming it entails a Fundamental Reset per PCIe r6.0 sec 5.8. The delay prescribed after a Fundamental Reset in PCIe r6.0 sec 6.6.1 is sought to be observed by: pci_pm_resume_noirq() pci_pm_bridge_power_up_actions() pci_bridge_wait_for_secondary_bus() However, pci_bridge_wait_for_secondary_bus() bails out if the bridge_d3 flag is not set. That flag indicates whether a bridge is allowed to suspend to D3cold at *runtime*. Hence *no* delay is observed on resume from system sleep if runtime D3cold is forbidden. That doesn't make any sense, so drop the bridge_d3 check from pci_bridge_wait_for_secondary_bus(). The purpose of the bridge_d3 check was probably to avoid delays if a bridge remained in D0 during suspend. However the sole caller of pci_bridge_wait_for_secondary_bus(), pci_pm_bridge_power_up_actions(), is only invoked if the previous power state was D3cold. Hence the additional bridge_d3 check seems superfluous. Fixes: ad9001f2f411 ("PCI/PM: Add missing link delays required by the PCIe spec") Link: https://lore.kernel.org/r/eb37fa345285ec8bacabbf06b020b803f77bdd3d.1673769517.git.lukas@wunner.de Tested-by: Ravi Kishore Koppuravuri Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Reviewed-by: Mika Westerberg Reviewed-by: Kuppuswamy Sathyanarayanan Cc: stable@vger.kernel.org # v5.5+ --- drivers/pci/pci.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index fba9548..f43f3e8 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4964,7 +4964,7 @@ void pci_bridge_wait_for_secondary_bus(struct pci_dev *dev) if (pci_dev_is_disconnected(dev)) return; - if (!pci_is_bridge(dev) || !dev->bridge_d3) + if (!pci_is_bridge(dev)) return; down_read(&pci_bus_sem); -- 2.7.4