Messages in this thread Patch in this message | | | Date | Tue, 7 Aug 2007 00:50:13 +0900 | From | "Joonwoo Park" <> | Subject | Re: [PATCH] kexec: fix pci device initialization fail after kexec (2.6.23-rc2). (Related to e1000 doesn't resume properly from standby) |
| |
2007/8/6, Rafael J. Wysocki <rjw@sisk.pl>: > On Monday, 6 August 2007 15:42, Joonwoo Park wrote: > > Hi. > > I think that the pci_set_power_state() has bug. > > The specification says that some delays is required. > > And they are in place, AFAICS (from drivers/pci/pci.c): > > /* 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); >
The problem is occurred when state is 'PCI_D0', so those codes can't cover it. But pci pm specification 5.4.1 says that when programmed to D0 the equivalent of a warm reset, delay for the duration of the D3hot to D0 Uninitialized state transition (10ms) to pci signal drivers remain disabled is required.
> > Simon, please can I know whether it works to you? > > It is seems to the things are related. > > > > Joonwoo Park. > > > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > > index 37c00f6..9f78064 100644 > > --- a/drivers/pci/pci.c > > +++ b/drivers/pci/pci.c > > @@ -493,8 +493,14 @@ pci_set_power_state(struct pci_dev *dev, pci_power_t state) > > * restore at least the BARs so that the device will be > > * accessible to its driver. > > */ > > - if (need_restore) > > + if (need_restore) { > > + /* The specification also says that "Must ensure that all of > > + * its PCI signal drivers remain disabled for the duration of > > + * the D3hot to D0 Uninitialized state transition". > > + */ > > + msleep(10); > > It's too late for the delay. >
How about this?
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 37c00f6..974dd04 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -471,6 +471,8 @@ pci_set_power_state(struct pci_dev *dev, pci_power_t state) msleep(pci_pm_d3_delay); else if (state == PCI_D2 || dev->current_state == PCI_D2) udelay(200); + else if (state == PCI_D0) + msleep(10);
/* * Give firmware a chance to be called, such as ACPI _PRx, _PSx
> > pci_restore_bars(dev); > > + } > > > > return 0; > > } > > Greetings, > Rafael > > > -- > "Premature optimization is the root of all evil." - Donald Knuth >
Thanks, Joonwoo Park. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |