| Message ID | 200901310031.37660.rjw@sisk.pl |
|---|---|
| State | RFC, archived |
| Delegated to: | David Miller |
| Headers | show |
On Sat, 31 Jan 2009, Rafael J. Wysocki wrote: > > I wonder if this change makes any difference: > > --- linux-2.6.orig/drivers/pci/pci-driver.c > +++ linux-2.6/drivers/pci/pci-driver.c > @@ -501,6 +501,9 @@ static int pci_pm_suspend(struct device > if (pci_has_legacy_pm_support(pci_dev)) > return pci_legacy_suspend(dev, PMSG_SUSPEND); > > + if (!drv || !drv->pm) > + return 0; > + > if (drv && drv->pm && drv->pm->suspend) { > error = drv->pm->suspend(dev); > suspend_report_result(drv->pm->suspend, error); I don't think that's right. Now you don't end up calling pci_pm_default_suspend_generic() at all, and this no pci_save_state(). But I think it could easily be the call to pci_disable_enabled_device(). It does that if (atomic_read(&dev->enable_cnt)) do_pci_disable_device(dev); and that ends up disabling PCI_COMMAND_MASTER and then calling pcibios_disable_device(). Any device we have ever done pci_enable_device() on would trigger this, which includes PCIE bridges, for example. And while the pcie driver does that pcie_portdrv_restore_config -> pci_enable_device(dev); thing to re-enable it, that's a no-op since the enable_count is already non-zero. And we do try to restore it (pci_restore_standard_config() will call pci_restore_state()), but since we've done the pci_disable_enabled_device() _before_ we did the pci_save_state(), we now restore a non-working setup. I think. The rules are too damn subtle there. Rafael, can you look around a bit? Linus -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Saturday 31 January 2009, Linus Torvalds wrote: > > On Sat, 31 Jan 2009, Rafael J. Wysocki wrote: > > > > I wonder if this change makes any difference: > > > > --- linux-2.6.orig/drivers/pci/pci-driver.c > > +++ linux-2.6/drivers/pci/pci-driver.c > > @@ -501,6 +501,9 @@ static int pci_pm_suspend(struct device > > if (pci_has_legacy_pm_support(pci_dev)) > > return pci_legacy_suspend(dev, PMSG_SUSPEND); > > > > + if (!drv || !drv->pm) > > + return 0; > > + > > if (drv && drv->pm && drv->pm->suspend) { > > error = drv->pm->suspend(dev); > > suspend_report_result(drv->pm->suspend, error); > > I don't think that's right. Now you don't end up calling > pci_pm_default_suspend_generic() at all, and this no pci_save_state(). > > But I think it could easily be the call to pci_disable_enabled_device(). > It does that > > if (atomic_read(&dev->enable_cnt)) > do_pci_disable_device(dev); > > and that ends up disabling PCI_COMMAND_MASTER and then calling > pcibios_disable_device(). > > Any device we have ever done pci_enable_device() on would trigger this, > which includes PCIE bridges, for example. And while the pcie driver does > that > > pcie_portdrv_restore_config -> > pci_enable_device(dev); > > thing to re-enable it, that's a no-op since the enable_count is already > non-zero. > > And we do try to restore it (pci_restore_standard_config() will call > pci_restore_state()), but since we've done the > pci_disable_enabled_device() _before_ we did the pci_save_state(), we now > restore a non-working setup. > > I think. The rules are too damn subtle there. Rafael, can you look around > a bit? Sure, I'm looking at it right now. Rafael -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Saturday 31 January 2009, Linus Torvalds wrote: > > On Sat, 31 Jan 2009, Rafael J. Wysocki wrote: > > > > I wonder if this change makes any difference: > > > > --- linux-2.6.orig/drivers/pci/pci-driver.c > > +++ linux-2.6/drivers/pci/pci-driver.c > > @@ -501,6 +501,9 @@ static int pci_pm_suspend(struct device > > if (pci_has_legacy_pm_support(pci_dev)) > > return pci_legacy_suspend(dev, PMSG_SUSPEND); > > > > + if (!drv || !drv->pm) > > + return 0; > > + > > if (drv && drv->pm && drv->pm->suspend) { > > error = drv->pm->suspend(dev); > > suspend_report_result(drv->pm->suspend, error); > > I don't think that's right. Now you don't end up calling > pci_pm_default_suspend_generic() at all, and this no pci_save_state(). > > But I think it could easily be the call to pci_disable_enabled_device(). > It does that > > if (atomic_read(&dev->enable_cnt)) > do_pci_disable_device(dev); > > and that ends up disabling PCI_COMMAND_MASTER and then calling > pcibios_disable_device(). pci_disable_enabled_device() is not called for the PCIe port driver, because it has the legacy PM support. What happens is pci_pm_suspend(port) -> pci_legacy_suspend(port) -> pcie_portdrv_suspend(port) [this doesn't save the state] pci_save_state(port) and then, with interrupts off pci_pm_suspend_noirq(port) -> pci_legacy_suspend_late(port) -> pcie_portdrv_suspend_late(port) -> pci_save_state(port) and I suspect this last pci_save_state() breaks things. I'm not sure why, though. Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
--- linux-2.6.orig/drivers/pci/pci-driver.c +++ linux-2.6/drivers/pci/pci-driver.c @@ -501,6 +501,9 @@ static int pci_pm_suspend(struct device if (pci_has_legacy_pm_support(pci_dev)) return pci_legacy_suspend(dev, PMSG_SUSPEND); + if (!drv || !drv->pm) + return 0; + if (drv && drv->pm && drv->pm->suspend) { error = drv->pm->suspend(dev); suspend_report_result(drv->pm->suspend, error);