From aa8c6c93747f7b55fa11e1624fec8ca33763a805 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 16 Jan 2009 21:54:43 +0100 Subject: PCI PM: Restore standard config registers of all devices early There is a problem in our handling of suspend-resume of PCI devices that many of them have their standard config registers restored with interrupts enabled and they are put into the full power state with interrupts enabled as well. This may lead to the following scenario: * an interrupt vector is shared between two or more devices * one device is resumed earlier and generates an interrupt * the interrupt handler of another device tries to handle it and attempts to access the device the config space of which hasn't been restored yet and/or which still is in a low power state * the system crashes as a result To prevent this from happening we should restore the standard configuration registers of all devices with interrupts disabled and we should put them into the D0 power state right after that. Unfortunately, this cannot be done using the existing pci_set_power_state(), because it can sleep. Also, to do it we have to make sure that the config spaces of all devices were actually saved during suspend. Signed-off-by: Rafael J. Wysocki Acked-by: Linus Torvalds Signed-off-by: Jesse Barnes --- drivers/pci/pci.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 57 insertions(+), 6 deletions(-) (limited to 'drivers/pci/pci.c') diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index e491fdedf705..17bd9325a245 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -22,7 +22,7 @@ #include /* isa_dma_bridge_buggy */ #include "pci.h" -unsigned int pci_pm_d3_delay = 10; +unsigned int pci_pm_d3_delay = PCI_PM_D3_WAIT; #ifdef CONFIG_PCI_DOMAINS int pci_domains_supported = 1; @@ -426,6 +426,7 @@ static inline int platform_pci_sleep_wake(struct pci_dev *dev, bool enable) * given PCI device * @dev: PCI device to handle. * @state: PCI power state (D0, D1, D2, D3hot) to put the device into. + * @wait: If 'true', wait for the device to change its power state * * RETURN VALUE: * -EINVAL if the requested state is invalid. @@ -435,7 +436,7 @@ static inline int platform_pci_sleep_wake(struct pci_dev *dev, bool enable) * 0 if device's power state has been successfully changed. */ static int -pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state) +pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state, bool wait) { u16 pmcsr; bool need_restore = false; @@ -480,8 +481,10 @@ pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state) break; case PCI_UNKNOWN: /* Boot-up */ if ((pmcsr & PCI_PM_CTRL_STATE_MASK) == PCI_D3hot - && !(pmcsr & PCI_PM_CTRL_NO_SOFT_RESET)) + && !(pmcsr & PCI_PM_CTRL_NO_SOFT_RESET)) { need_restore = true; + wait = true; + } /* Fall-through: force to D0 */ default: pmcsr = 0; @@ -491,12 +494,15 @@ pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state) /* enter specified state */ pci_write_config_word(dev, dev->pm_cap + PCI_PM_CTRL, pmcsr); + if (!wait) + return 0; + /* Mandatory power management transition delays */ /* see PCI PM 1.1 5.6.1 table 18 */ if (state == PCI_D3hot || dev->current_state == PCI_D3hot) msleep(pci_pm_d3_delay); else if (state == PCI_D2 || dev->current_state == PCI_D2) - udelay(200); + udelay(PCI_PM_D2_DELAY); dev->current_state = state; @@ -515,7 +521,7 @@ pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state) if (need_restore) pci_restore_bars(dev); - if (dev->bus->self) + if (wait && dev->bus->self) pcie_aspm_pm_state_change(dev->bus->self); return 0; @@ -585,7 +591,7 @@ int pci_set_power_state(struct pci_dev *dev, pci_power_t state) if (state == PCI_D3hot && (dev->dev_flags & PCI_DEV_FLAGS_NO_D3)) return 0; - error = pci_raw_set_power_state(dev, state); + error = pci_raw_set_power_state(dev, state, true); if (state > PCI_D0 && platform_pci_power_manageable(dev)) { /* Allow the platform to finalize the transition */ @@ -730,6 +736,7 @@ pci_save_state(struct pci_dev *dev) /* XXX: 100% dword access ok here? */ for (i = 0; i < 16; i++) pci_read_config_dword(dev, i * 4,&dev->saved_config_space[i]); + dev->state_saved = true; if ((i = pci_save_pcie_state(dev)) != 0) return i; if ((i = pci_save_pcix_state(dev)) != 0) @@ -1373,6 +1380,50 @@ void pci_allocate_cap_save_buffers(struct pci_dev *dev) "unable to preallocate PCI-X save buffer\n"); } +/** + * pci_restore_standard_config - restore standard config registers of PCI device + * @dev: PCI device to handle + * + * This function assumes that the device's configuration space is accessible. + * If the device needs to be powered up, the function will wait for it to + * change the state. + */ +int pci_restore_standard_config(struct pci_dev *dev) +{ + pci_power_t prev_state; + int error; + + pci_restore_state(dev); + pci_update_current_state(dev, PCI_D0); + + prev_state = dev->current_state; + if (prev_state == PCI_D0) + return 0; + + error = pci_raw_set_power_state(dev, PCI_D0, false); + if (error) + return error; + + if (pci_is_bridge(dev)) { + if (prev_state > PCI_D1) + mdelay(PCI_PM_BUS_WAIT); + } else { + switch(prev_state) { + case PCI_D3cold: + case PCI_D3hot: + mdelay(pci_pm_d3_delay); + break; + case PCI_D2: + udelay(PCI_PM_D2_DELAY); + break; + } + } + + dev->current_state = PCI_D0; + + return 0; +} + /** * pci_enable_ari - enable ARI forwarding if hardware support it * @dev: the PCI device -- cgit From 48f67f54a53bb68619a63c3f38cf7f502ed74b1d Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 22 Jan 2009 23:38:31 +0100 Subject: PCI PM: Power up devices before restoring their state Devices that have MSI-X enabled before suspend to RAM or hibernation and that are in a low power state during resume will not be handled correctly by pci_restore_standard_config(). Namely, it first calls pci_restore_state() which calls pci_restore_msi_state(), which in turn executes __pci_restore_msix_state() that accesses the device's memory space to restore the contents of the MSI-X table. However, if the device is in a low power state at this point, it's memory space is not accessible. The easiest way to fix this potential problem is to make pci_restore_standard_config() call pci_restore_state() after it has put the device into the full power state, D0. Fortunately, all of this is done with interrupts off, so the change of ordering should not cause any trouble. Signed-off-by: Rafael J. Wysocki Signed-off-by: Jesse Barnes --- drivers/pci/pci.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/pci/pci.c') diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 17bd9325a245..f0aa3d533839 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1393,12 +1393,11 @@ int pci_restore_standard_config(struct pci_dev *dev) pci_power_t prev_state; int error; - pci_restore_state(dev); pci_update_current_state(dev, PCI_D0); prev_state = dev->current_state; if (prev_state == PCI_D0) - return 0; + goto Restore; error = pci_raw_set_power_state(dev, PCI_D0, false); if (error) @@ -1421,7 +1420,8 @@ int pci_restore_standard_config(struct pci_dev *dev) dev->current_state = PCI_D0; - return 0; + Restore: + return pci_restore_state(dev); } /** -- cgit From 476e7faefc43f106a90b5c96166c59b75de19d30 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 22 Jan 2009 23:39:57 +0100 Subject: PCI PM: Do not wait for buses in B2 or B3 during resume pci_restore_standard_config() adds extra delay for PCI buses in low power states (B2 or B3), but this is only correct for buses in B2, because the buses in B3 are reset when they are put back into B0. Thus we should wait for such buses to settle after the reset, but it's not a good idea to wait that long (1.1 s) with interrupts off. On the other hand, we have never waited for buses in B2 and B3 during resume and it seems reasonable to go back to this well tested behaviour. Signed-off-by: Rafael J. Wysocki Signed-off-by: Jesse Barnes --- drivers/pci/pci.c | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) (limited to 'drivers/pci/pci.c') diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index f0aa3d533839..48807556b47a 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1403,19 +1403,19 @@ int pci_restore_standard_config(struct pci_dev *dev) if (error) return error; - if (pci_is_bridge(dev)) { - if (prev_state > PCI_D1) - mdelay(PCI_PM_BUS_WAIT); - } else { - switch(prev_state) { - case PCI_D3cold: - case PCI_D3hot: - mdelay(pci_pm_d3_delay); - break; - case PCI_D2: - udelay(PCI_PM_D2_DELAY); - break; - } + /* + * This assumes that we won't get a bus in B2 or B3 from the BIOS, but + * we've made this assumption forever and it appears to be universally + * satisfied. + */ + switch(prev_state) { + case PCI_D3cold: + case PCI_D3hot: + mdelay(pci_pm_d3_delay); + break; + case PCI_D2: + udelay(PCI_PM_D2_DELAY); + break; } dev->current_state = PCI_D0; -- cgit