Hi Vidya, On Thu, Jan 19, 2023 at 5:49 PM Vidya Sagar <vidyas@xxxxxxxxxx> wrote: > > Skip save and restore of ASPM L1 Sub-States specific registers if they > are not already enabled in the system. This is to avoid issues observed > on certain platforms during restoration process, particularly when > restoring the L1SS registers contents. > > BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=216782 > Signed-off-by: Vidya Sagar <vidyas@xxxxxxxxxx> > --- > drivers/pci/pcie/aspm.c | 19 ++++++++++++++++++- > 1 file changed, 18 insertions(+), 1 deletion(-) > > diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c > index 53a1fa306e1e..5d3f09b0a6a9 100644 > --- a/drivers/pci/pcie/aspm.c > +++ b/drivers/pci/pcie/aspm.c > @@ -757,15 +757,29 @@ static void pcie_config_aspm_l1ss(struct pcie_link_state *link, u32 state) > PCI_L1SS_CTL1_L1SS_MASK, val); > } > > +static bool skip_l1ss_restore; Maybe move it inside "struct pci_dev"? Kai-Heng > + > void pci_save_aspm_l1ss_state(struct pci_dev *dev) > { > struct pci_cap_saved_state *save_state; > u16 l1ss = dev->l1ss; > - u32 *cap; > + u32 *cap, val; > > if (!l1ss) > return; > > + /* > + * Skip save and restore of L1 Sub-States registers if they are not > + * already enabled in the system > + */ > + pci_read_config_dword(dev, l1ss + PCI_L1SS_CTL1, &val); > + if (!(val & PCI_L1SS_CTL1_L1SS_MASK)) { > + skip_l1ss_restore = 1; > + return; > + } > + > + skip_l1ss_restore = 0; > + > save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_L1SS); > if (!save_state) > return; > @@ -784,6 +798,9 @@ void pci_restore_aspm_l1ss_state(struct pci_dev *dev) > if (!l1ss) > return; > > + if (skip_l1ss_restore) > + return; > + > save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_L1SS); > if (!save_state) > return; > -- > 2.17.1 >
