Messages in this thread | | | Date | Fri, 2 Sep 2022 16:57:32 -0700 | Subject | Re: [PATCH v2 1/3] PCI/PTM: Preserve PTM Root Select | From | Sathyanarayanan Kuppuswamy <> |
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Hi,
On 9/2/22 4:35 PM, Bjorn Helgaas wrote: > From: Bjorn Helgaas <bhelgaas@google.com> > > When disabling PTM, there's no need to clear the Root Select bit. We > disable PTM during suspend, and we want to re-enable it during resume. > Clearing Root Select here makes re-enabling more complicated. > > Per PCIe r6.0, sec 7.9.15.3, "When set, if the PTM Enable bit is also Set, > this Time Source is the PTM Root," so if PTM Enable is cleared, the value > of Root Select should be irrelevant. > > Preserve Root Select to simplify re-enabling PTM. > > Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> > Cc: David E. Box <david.e.box@linux.intel.com> > ---
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> drivers/pci/pcie/ptm.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/pci/pcie/ptm.c b/drivers/pci/pcie/ptm.c > index 368a254e3124..b6a417247ce3 100644 > --- a/drivers/pci/pcie/ptm.c > +++ b/drivers/pci/pcie/ptm.c > @@ -42,7 +42,7 @@ void pci_disable_ptm(struct pci_dev *dev) > return; > > pci_read_config_word(dev, ptm + PCI_PTM_CTRL, &ctrl); > - ctrl &= ~(PCI_PTM_CTRL_ENABLE | PCI_PTM_CTRL_ROOT); > + ctrl &= ~PCI_PTM_CTRL_ENABLE; > pci_write_config_word(dev, ptm + PCI_PTM_CTRL, ctrl); > } >
-- Sathyanarayanan Kuppuswamy Linux Kernel Developer
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