| Message ID | PU1P153MB01695867B01987A8C239A8CCBFD70@PU1P153MB0169.APCP153.PROD.OUTLOOK.COM (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
| Series | PCI: PM: Also move to D0 before calling pci_legacy_resume_early() | expand |
On Thu, Aug 08, 2019 at 06:46:51PM +0000, Dexuan Cui wrote: > > In pci_legacy_suspend_late(), the device state is moved to PCI_UNKNOWN. > In pci_pm_thaw_noirq(), the state is supposed to be moved back to PCI_D0, > but the current code misses the pci_legacy_resume_early() path, so the > state remains in PCI_UNKNOWN in that path, and during hiberantion this > causes an error for the Mellanox VF driver, which fails to enable > MSI-X: pci_msi_supported() is false due to dev->current_state != PCI_D0: s/hiberantion/hibernation/ Actually, it sounds more like "during *resume*, this causes an error", so maybe you want s/hiberantion/resume/ instead? > mlx4_core a6d1:00:02.0: Detected virtual function - running in slave mode > mlx4_core a6d1:00:02.0: Sending reset > mlx4_core a6d1:00:02.0: Sending vhcr0 > mlx4_core a6d1:00:02.0: HCA minimum page size:512 > mlx4_core a6d1:00:02.0: Timestamping is not supported in slave mode > mlx4_core a6d1:00:02.0: INTx is not supported in multi-function mode, aborting > PM: dpm_run_callback(): pci_pm_thaw+0x0/0xd7 returns -95 > PM: Device a6d1:00:02.0 failed to thaw: error -95 > > Signed-off-by: Dexuan Cui <decui@microsoft.com> > --- > drivers/pci/pci-driver.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c > index 36dbe960306b..27dfc68db9e7 100644 > --- a/drivers/pci/pci-driver.c > +++ b/drivers/pci/pci-driver.c > @@ -1074,15 +1074,16 @@ static int pci_pm_thaw_noirq(struct device *dev) > return error; > } > > - if (pci_has_legacy_pm_support(pci_dev)) > - return pci_legacy_resume_early(dev); > - > /* > * pci_restore_state() requires the device to be in D0 (because of MSI > * restoration among other things), so force it into D0 in case the > * driver's "freeze" callbacks put it into a low-power state directly. > */ > pci_set_power_state(pci_dev, PCI_D0); > + > + if (pci_has_legacy_pm_support(pci_dev)) > + return pci_legacy_resume_early(dev); > + > pci_restore_state(pci_dev); > > if (drv && drv->pm && drv->pm->thaw_noirq) > -- > 2.19.1 >
> From: Bjorn Helgaas <helgaas@kernel.org> > Sent: Thursday, August 8, 2019 12:19 PM > To: Dexuan Cui <decui@microsoft.com> > > On Thu, Aug 08, 2019 at 06:46:51PM +0000, Dexuan Cui wrote: > > > > In pci_legacy_suspend_late(), the device state is moved to PCI_UNKNOWN. > > In pci_pm_thaw_noirq(), the state is supposed to be moved back to PCI_D0, > > but the current code misses the pci_legacy_resume_early() path, so the > > state remains in PCI_UNKNOWN in that path, and during hiberantion this > > causes an error for the Mellanox VF driver, which fails to enable > > MSI-X: pci_msi_supported() is false due to dev->current_state != PCI_D0: > > s/hiberantion/hibernation/ Thanks for spoting this typo! :-) > Actually, it sounds more like "during *resume*, this causes an error", > so maybe you want s/hiberantion/resume/ instead? Yes, it's during "resume", and to be more accurate, it happens during the "resume" of the "thaw" phase: when we run "echo disk > /sys/power/state", first the kernel "freezes" all the devices and create a hibernation image, then the kernel "thaws" the devices including the disk/NIC, and writes the memory to the disk and powers down. This patch fixes the error message for the Mellanox VF driver in this phase. When the system starts again, a fresh kernel starts to run, and when the kernel detects that a hibernation image was saved, the kernel "quiesces" the devices, and "restores" the devices from the saved image. Here device_resume_noirq() -> ... -> pci_pm_restore_noirq() -> pci_pm_default_resume_early() -> pci_power_up() moves the device states back to PCI_D0. This path is not broken and doesn't need my patch. Thanks, -- Dexuan
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index 36dbe960306b..27dfc68db9e7 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -1074,15 +1074,16 @@ static int pci_pm_thaw_noirq(struct device *dev) return error; } - if (pci_has_legacy_pm_support(pci_dev)) - return pci_legacy_resume_early(dev); - /* * pci_restore_state() requires the device to be in D0 (because of MSI * restoration among other things), so force it into D0 in case the * driver's "freeze" callbacks put it into a low-power state directly. */ pci_set_power_state(pci_dev, PCI_D0); + + if (pci_has_legacy_pm_support(pci_dev)) + return pci_legacy_resume_early(dev); + pci_restore_state(pci_dev); if (drv && drv->pm && drv->pm->thaw_noirq)
In pci_legacy_suspend_late(), the device state is moved to PCI_UNKNOWN. In pci_pm_thaw_noirq(), the state is supposed to be moved back to PCI_D0, but the current code misses the pci_legacy_resume_early() path, so the state remains in PCI_UNKNOWN in that path, and during hiberantion this causes an error for the Mellanox VF driver, which fails to enable MSI-X: pci_msi_supported() is false due to dev->current_state != PCI_D0: mlx4_core a6d1:00:02.0: Detected virtual function - running in slave mode mlx4_core a6d1:00:02.0: Sending reset mlx4_core a6d1:00:02.0: Sending vhcr0 mlx4_core a6d1:00:02.0: HCA minimum page size:512 mlx4_core a6d1:00:02.0: Timestamping is not supported in slave mode mlx4_core a6d1:00:02.0: INTx is not supported in multi-function mode, aborting PM: dpm_run_callback(): pci_pm_thaw+0x0/0xd7 returns -95 PM: Device a6d1:00:02.0 failed to thaw: error -95 Signed-off-by: Dexuan Cui <decui@microsoft.com> --- drivers/pci/pci-driver.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)