On Tue, 2024-03-05 at 16:03 -0600, Bjorn Helgaas wrote: > [+to Sathy, David in case you want to update your Reviewed-by] > > On Thu, Feb 22, 2024 at 11:14:36PM +0530, Vidya Sagar wrote: > > Many PCIe device drivers save the configuration state of their respective > > devices during probe and restore the same when their 'slot_reset' hook > > is called through PCIe Error Recovery Handler. > > > > If the system has a change in ASPM policy after the driver's probe is > > called and before error event occurred, 'slot_reset' hook restores the > > PCIe configuration state to what it was at the time of probe but not to > > what it was just before the occurrence of the error event. > > This effectively leads to a mismatch in the ASPM configuration between > > the device and its upstream parent device. > > > > Update the saved configuration state of the device with the latest info > > whenever there is a change w.r.t ASPM policy. > > > > Signed-off-by: Vidya Sagar <vidyas@xxxxxxxxxx> > > > -void pci_save_aspm_state(struct pci_dev *pdev); > > +void pci_save_aspm_l1ss_state(struct pci_dev *pdev); > > I rebased this again on top of my pci/aspm updates to remove the need > for the rename above. > > > +static void pci_save_aspm_state(struct pci_dev *dev) > > +{ > > + struct pci_cap_saved_state *save_state; > > + u16 *cap; > > + > > + if (!pci_is_pcie(dev)) > > + return; > > + > > + save_state = pci_find_saved_cap(dev, PCI_CAP_ID_EXP); > > + if (!save_state) > > + return; > > + > > + cap = (u16 *)&save_state->cap.data[0]; > > + pcie_capability_read_word(dev, PCI_EXP_LNKCTL, &cap[1]); > > And I changed this part so it only updates the PCI_EXP_LNKCTL_ASPMC > bits, not the entire LNKCTL. > > Updating the entire saved register probably wouldn't *break* anything, > but it could randomly hide other LNKCTL changes depending on whether > or not ASPM configuration was changed in the interim. For example: > > - driver .probe() saves LNKCTL > - LNKCTL changes some non-ASPMC thing via setpci or other mechanism > - save_state updated via pcie_config_aspm_link() > > A restore in .slot_reset() would restore different LNKCTL values for > the non-ASPMC change depending on whether pcie_config_aspm_link() was > used. > > I applied it on pci/aspm for v6.9. Please take a look and make sure > it still does what you need: > https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git/commit/?h=aspm&id=a6315434436d587f70e489e6365c5b7e20176a71 > > Sathy and David, I didn't add your Reviewed-by because I didn't want > to presume that you were OK with my changes. But I'd be more than > happy to add them if you take a look. > > Bjorn > > > +} > > + > > void pci_aspm_get_l1ss(struct pci_dev *pdev) > > { > > /* Read L1 PM substate capabilities */ > > pdev->l1ss = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_L1SS); > > } > > > > -void pci_save_aspm_state(struct pci_dev *pdev) > > +void pci_save_aspm_l1ss_state(struct pci_dev *pdev) > > { > > struct pci_cap_saved_state *save_state; > > u16 l1ss = pdev->l1ss; > > @@ -309,10 +325,12 @@ static void pcie_set_clkpm_nocheck(struct > > pcie_link_state *link, int enable) > > struct pci_bus *linkbus = link->pdev->subordinate; > > u32 val = enable ? PCI_EXP_LNKCTL_CLKREQ_EN : 0; > > > > - list_for_each_entry(child, &linkbus->devices, bus_list) > > + list_for_each_entry(child, &linkbus->devices, bus_list) { > > pcie_capability_clear_and_set_word(child, PCI_EXP_LNKCTL, > > PCI_EXP_LNKCTL_CLKREQ_EN, > > val); > > + pci_save_aspm_state(child); > > + } > > link->clkpm_enabled = !!enable; > > } > > > > @@ -931,6 +949,12 @@ static void pcie_config_aspm_link(struct > > pcie_link_state *link, u32 state) > > pcie_config_aspm_dev(parent, upstream); > > > > link->aspm_enabled = state; > > + > > + /* Update latest ASPM configuration in saved context */ > > + pci_save_aspm_state(link->downstream); > > + pci_save_aspm_l1ss_state(link->downstream); > > + pci_save_aspm_state(parent); > > + pci_save_aspm_l1ss_state(parent); > > } > > > > static void pcie_config_aspm_path(struct pcie_link_state *link) > > -- > > 2.25.1 > > Reviewed-by: David E. Box <david.e.box@xxxxxxxxxxxxxxx>