From: Rafael J. Wysocki Date: Tue, 22 Jun 2021 15:35:18 +0000 (+0200) Subject: Revert "PCI: PM: Do not read power state in pci_enable_device_flags()" X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=e9695e4d26d210b81c9c8a11f6983c1190a3a9cc;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git Revert "PCI: PM: Do not read power state in pci_enable_device_flags()" [ Upstream commit 4d6035f9bf4ea12776322746a216e856dfe46698 ] Revert commit 4514d991d992 ("PCI: PM: Do not read power state in pci_enable_device_flags()") that is reported to cause PCI device initialization issues on some systems. BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=213481 Link: https://lore.kernel.org/linux-acpi/YNDoGICcg0V8HhpQ@eldamar.lan Reported-by: Michael Reported-by: Salvatore Bonaccorso Fixes: 4514d991d992 ("PCI: PM: Do not read power state in pci_enable_device_flags()") Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 1993e5e28ea7..c847b5554db6 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1378,11 +1378,21 @@ static int pci_enable_device_flags(struct pci_dev *dev, unsigned long flags) int err; int i, bars = 0; - if (atomic_inc_return(&dev->enable_cnt) > 1) { - pci_update_current_state(dev, dev->current_state); - return 0; /* already enabled */ + /* + * Power state could be unknown at this point, either due to a fresh + * boot or a device removal call. So get the current power state + * so that things like MSI message writing will behave as expected + * (e.g. if the device really is in D0 at enable time). + */ + if (dev->pm_cap) { + u16 pmcsr; + pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr); + dev->current_state = (pmcsr & PCI_PM_CTRL_STATE_MASK); } + if (atomic_inc_return(&dev->enable_cnt) > 1) + return 0; /* already enabled */ + bridge = pci_upstream_bridge(dev); if (bridge) pci_enable_bridge(bridge);