Path: csiph.com!news.redatomik.org!aioe.org!bofh.it!news.nic.it!robomod From: "Rafael J. Wysocki" Newsgroups: linux.kernel Subject: [PATCH] PCI / PM: Fix native PME handling during system suspend/resume Date: Thu, 06 Jul 2017 02:40:01 +0200 Message-ID: User-Agent: KMail/4.14.10 (Linux/4.12.0-rc1+; KDE/4.14.9; x86_64; ; ) MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: robomod@news.nic.it List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Approved: robomod@news.nic.it Lines: 136 Organization: linux.* mail to news gateway X-Original-Cc: Bjorn Helgaas , Mika Westerberg , Linux PM , LKML , Sadashiva Rao Pv , Naresh Solanki , "Rafael J. Wysocki" X-Original-Date: Thu, 06 Jul 2017 02:32:02 +0200 X-Original-Message-ID: <3705400.FL23FbEzsj@aspire.rjw.lan> X-Original-Sender: linux-kernel-owner@vger.kernel.org Xref: csiph.com linux.kernel:1681973 From: Rafael J. Wysocki Commit 76cde7e49590 (PCI / PM: Make PCIe PME interrupts wake up from suspend-to-idle) went too far with preventing pcie_pme_work_fn() from clearing the root port's PME Status and re-enabling the PME interrupt which should be done for PMEs to work correctly after system resume. The failing scenario is as follows: 1. pcie_pme_suspend() finds that the PME IRQ should be designated for system wakeup, so it calls enable_irq_wake() and then sets data->suspend_level to PME_SUSPEND_WAKEUP. 2. PME interrupt happens at this point. 3. pcie_pme_irq() runs, disables the PME interrupt and queues up the execution of pcie_pme_work_fn(). 4. pcie_pme_work_fn() runs before pcie_pme_resume() and breaks out of the loop right away, because data->suspend_level is not PME_SUSPEND_NONE, and it doesn't re-enable the PME interrupt for the same reason. 5. pcie_pme_resume() runs and simply calls disable_irq_wake() without re-enabling the PME interrupt (because data->suspend_level is not PME_SUSPEND_NONE), so the PME interrupt remains disabled and the PME Status remains set. To fix this notice that there is no reason why pcie_pme_work_fn() should behave in a special way during system resume if the PME interrupt is not disabled by pcie_pme_suspend() and partially revert commit 76cde7e49590 and restore the previous (and correct) behavior of pcie_pme_work_fn(). Fixes: 76cde7e49590 (PCI / PM: Make PCIe PME interrupts wake up from suspend-to-idle) Reported-by: Naresh Solanki Signed-off-by: Rafael J. Wysocki --- drivers/pci/pcie/pme.c | 35 +++++++++++++---------------------- 1 file changed, 13 insertions(+), 22 deletions(-) Index: linux-pm/drivers/pci/pcie/pme.c =================================================================== --- linux-pm.orig/drivers/pci/pcie/pme.c +++ linux-pm/drivers/pci/pcie/pme.c @@ -40,17 +40,11 @@ static int __init pcie_pme_setup(char *s } __setup("pcie_pme=", pcie_pme_setup); -enum pme_suspend_level { - PME_SUSPEND_NONE = 0, - PME_SUSPEND_WAKEUP, - PME_SUSPEND_NOIRQ, -}; - struct pcie_pme_service_data { spinlock_t lock; struct pcie_device *srv; struct work_struct work; - enum pme_suspend_level suspend_level; + bool noirq; /* If set, keep the PME interrupt disabled. */ }; /** @@ -228,7 +222,7 @@ static void pcie_pme_work_fn(struct work spin_lock_irq(&data->lock); for (;;) { - if (data->suspend_level != PME_SUSPEND_NONE) + if (data->noirq) break; pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta); @@ -255,7 +249,7 @@ static void pcie_pme_work_fn(struct work spin_lock_irq(&data->lock); } - if (data->suspend_level == PME_SUSPEND_NONE) + if (!data->noirq) pcie_pme_interrupt_enable(port, true); spin_unlock_irq(&data->lock); @@ -378,7 +372,7 @@ static int pcie_pme_suspend(struct pcie_ { struct pcie_pme_service_data *data = get_service_data(srv); struct pci_dev *port = srv->port; - bool wakeup, wake_irq_enabled = false; + bool wakeup; int ret; if (device_may_wakeup(&port->dev)) { @@ -388,19 +382,16 @@ static int pcie_pme_suspend(struct pcie_ wakeup = pcie_pme_check_wakeup(port->subordinate); up_read(&pci_bus_sem); } - spin_lock_irq(&data->lock); if (wakeup) { ret = enable_irq_wake(srv->irq); - if (ret == 0) { - data->suspend_level = PME_SUSPEND_WAKEUP; - wake_irq_enabled = true; - } - } - if (!wake_irq_enabled) { - pcie_pme_interrupt_enable(port, false); - pcie_clear_root_pme_status(port); - data->suspend_level = PME_SUSPEND_NOIRQ; + if (!ret) + return 0; } + + spin_lock_irq(&data->lock); + pcie_pme_interrupt_enable(port, false); + pcie_clear_root_pme_status(port); + data->noirq = true; spin_unlock_irq(&data->lock); synchronize_irq(srv->irq); @@ -417,15 +408,15 @@ static int pcie_pme_resume(struct pcie_d struct pcie_pme_service_data *data = get_service_data(srv); spin_lock_irq(&data->lock); - if (data->suspend_level == PME_SUSPEND_NOIRQ) { + if (data->noirq) { struct pci_dev *port = srv->port; pcie_clear_root_pme_status(port); pcie_pme_interrupt_enable(port, true); + data->noirq = false; } else { disable_irq_wake(srv->irq); } - data->suspend_level = PME_SUSPEND_NONE; spin_unlock_irq(&data->lock); return 0;