On 2/15/24 10:24 PM, Jian-Hong Pan wrote: > The remapped PCIe Root Port and NVMe have PCI PM L1 substates capability, > but they are disabled originally. > > Here is a failed example on ASUS B1400CEAE: > > Capabilities: [900 v1] L1 PM Substates > L1SubCap: PCI-PM_L1.2+ PCI-PM_L1.1- ASPM_L1.2+ ASPM_L1.1- L1_PM_Substates+ > PortCommonModeRestoreTime=32us PortTPowerOnTime=10us > L1SubCtl1: PCI-PM_L1.2- PCI-PM_L1.1- ASPM_L1.2+ ASPM_L1.1- > T_CommonMode=0us LTR1.2_Threshold=0ns > L1SubCtl2: T_PwrOn=10us > > Power on all of the VMD remapped PCI devices before enable PCI-PM L1 PM > Substates by following PCI Express Base Specification Revision 6.0, section > 5.5.4. > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=218394 > Signed-off-by: Jian-Hong Pan <jhp@xxxxxxxxxxxxx> > --- Code wise it looks fine to me. Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx> > v2: > - Power on the VMD remapped devices with pci_set_power_state_locked() > - Prepare the PCIe LTR parameters before enable L1 Substates > - Add note into the comments of both pci_enable_link_state() and > pci_enable_link_state_locked() for kernel-doc. > - The original patch set can be split as individual patches. > > v3: > - Re-send for the missed version information. > - Split drivers/pci/pcie/aspm.c modification into following patches. > - Fix the comment for enasuring the PCI devices in D0. > > v4: > - The same > > drivers/pci/controller/vmd.c | 13 +++++++++---- > 1 file changed, 9 insertions(+), 4 deletions(-) > > diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c > index 87b7856f375a..6aca3f77724c 100644 > --- a/drivers/pci/controller/vmd.c > +++ b/drivers/pci/controller/vmd.c > @@ -751,11 +751,9 @@ static int vmd_pm_enable_quirk(struct pci_dev *pdev, void *userdata) > if (!(features & VMD_FEAT_BIOS_PM_QUIRK)) > return 0; > > - pci_enable_link_state_locked(pdev, PCIE_LINK_STATE_ALL); > - > pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_LTR); > if (!pos) > - return 0; > + goto out_enable_link_state; > > /* > * Skip if the max snoop LTR is non-zero, indicating BIOS has set it > @@ -763,7 +761,7 @@ static int vmd_pm_enable_quirk(struct pci_dev *pdev, void *userdata) > */ > pci_read_config_dword(pdev, pos + PCI_LTR_MAX_SNOOP_LAT, <r_reg); > if (!!(ltr_reg & (PCI_LTR_VALUE_MASK | PCI_LTR_SCALE_MASK))) > - return 0; > + goto out_enable_link_state; > > /* > * Set the default values to the maximum required by the platform to > @@ -775,6 +773,13 @@ static int vmd_pm_enable_quirk(struct pci_dev *pdev, void *userdata) > pci_write_config_dword(pdev, pos + PCI_LTR_MAX_SNOOP_LAT, ltr_reg); > pci_info(pdev, "VMD: Default LTR value set by driver\n"); > > +out_enable_link_state: Nit: Since you are also power on device, may be a generic name is better? Like out_state_change or update_device_state? But it is upto you. > + /* > + * Ensure devices are in D0 before enabling PCI-PM L1 PM Substates, per > + * PCIe r6.0, sec 5.5.4. > + */ > + pci_set_power_state_locked(pdev, PCI_D0); > + pci_enable_link_state_locked(pdev, PCIE_LINK_STATE_ALL); > return 0; > } > -- Sathyanarayanan Kuppuswamy Linux Kernel Developer
