Re: [PATCH V2] PCI/ASPM: Save/restore L1SS Capability for suspend/resume
From: Lukasz Majczak
Date: Fri Jul 22 2022 - 05:46:34 EST
pt., 22 lip 2022 o 09:31 Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> napisał(a):
>
> On Fri, Jul 15, 2022 at 6:38 PM Ben Chuang <benchuanggli@xxxxxxxxx> wrote:
> >
> > On Tue, Jul 5, 2022 at 2:00 PM Vidya Sagar <vidyas@xxxxxxxxxx> wrote:
> > >
> > > Previously ASPM L1 Substates control registers (CTL1 and CTL2) weren't
> > > saved and restored during suspend/resume leading to L1 Substates
> > > configuration being lost post-resume.
> > >
> > > Save the L1 Substates control registers so that the configuration is
> > > retained post-resume.
> > >
> > > Signed-off-by: Vidya Sagar <vidyas@xxxxxxxxxx>
> > > Tested-by: Abhishek Sahu <abhsahu@xxxxxxxxxx>
> >
> > Hi Vidya,
> >
> > I tested this patch on kernel v5.19-rc6.
> > The test device is GL9755 card reader controller on Intel i5-10210U RVP.
> > This patch can restore L1SS after suspend/resume.
> >
> > The test results are as follows:
> >
> > After Boot:
> > #lspci -d 17a0:9755 -vvv | grep -A5 "L1 PM Substates"
> > Capabilities: [110 v1] L1 PM Substates
> > L1SubCap: PCI-PM_L1.2+ PCI-PM_L1.1+ ASPM_L1.2+
> > ASPM_L1.1+ L1_PM_Substates+
> > PortCommonModeRestoreTime=255us
> > PortTPowerOnTime=3100us
> > L1SubCtl1: PCI-PM_L1.2+ PCI-PM_L1.1+ ASPM_L1.2+ ASPM_L1.1+
> > T_CommonMode=0us LTR1.2_Threshold=3145728ns
> > L1SubCtl2: T_PwrOn=3100us
> >
> >
> > After suspend/resume without this patch.
> > #lspci -d 17a0:9755 -vvv | grep -A5 "L1 PM Substates"
> > Capabilities: [110 v1] L1 PM Substates
> > L1SubCap: PCI-PM_L1.2+ PCI-PM_L1.1+ ASPM_L1.2+
> > ASPM_L1.1+ L1_PM_Substates+
> > PortCommonModeRestoreTime=255us
> > PortTPowerOnTime=3100us
> > 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
> >
> >
> > After suspend/resume with this patch.
> > #lspci -d 17a0:9755 -vvv | grep -A5 "L1 PM Substates"
> > Capabilities: [110 v1] L1 PM Substates
> > L1SubCap: PCI-PM_L1.2+ PCI-PM_L1.1+ ASPM_L1.2+
> > ASPM_L1.1+ L1_PM_Substates+
> > PortCommonModeRestoreTime=255us
> > PortTPowerOnTime=3100us
> > L1SubCtl1: PCI-PM_L1.2+ PCI-PM_L1.1+ ASPM_L1.2+ ASPM_L1.1+
> > T_CommonMode=0us LTR1.2_Threshold=3145728ns
> > L1SubCtl2: T_PwrOn=3100us
> >
> >
> > Tested-by: Ben Chuang <benchuanggli@xxxxxxxxx>
>
> Forgot to add mine:
> Tested-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
>
> >
> > Best regards,
> > Ben Chuang
> >
> >
> > > ---
> > > Hi,
> > > Kenneth R. Crudup <kenny@xxxxxxxxx>, Could you please verify this patch
> > > on your laptop (Dell XPS 13) one last time?
> > > IMHO, the regression observed on your laptop with an old version of the patch
> > > could be due to a buggy old version BIOS in the laptop.
> > >
> > > Thanks,
> > > Vidya Sagar
> > >
> > > drivers/pci/pci.c | 7 +++++++
> > > drivers/pci/pci.h | 4 ++++
> > > drivers/pci/pcie/aspm.c | 44 +++++++++++++++++++++++++++++++++++++++++
> > > 3 files changed, 55 insertions(+)
> > >
> > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > > index cfaf40a540a8..aca05880aaa3 100644
> > > --- a/drivers/pci/pci.c
> > > +++ b/drivers/pci/pci.c
> > > @@ -1667,6 +1667,7 @@ int pci_save_state(struct pci_dev *dev)
> > > return i;
> > >
> > > pci_save_ltr_state(dev);
> > > + pci_save_aspm_l1ss_state(dev);
> > > pci_save_dpc_state(dev);
> > > pci_save_aer_state(dev);
> > > pci_save_ptm_state(dev);
> > > @@ -1773,6 +1774,7 @@ void pci_restore_state(struct pci_dev *dev)
> > > * LTR itself (in the PCIe capability).
> > > */
> > > pci_restore_ltr_state(dev);
> > > + pci_restore_aspm_l1ss_state(dev);
> > >
> > > pci_restore_pcie_state(dev);
> > > pci_restore_pasid_state(dev);
> > > @@ -3489,6 +3491,11 @@ void pci_allocate_cap_save_buffers(struct pci_dev *dev)
> > > if (error)
> > > pci_err(dev, "unable to allocate suspend buffer for LTR\n");
> > >
> > > + error = pci_add_ext_cap_save_buffer(dev, PCI_EXT_CAP_ID_L1SS,
> > > + 2 * sizeof(u32));
> > > + if (error)
> > > + pci_err(dev, "unable to allocate suspend buffer for ASPM-L1SS\n");
> > > +
> > > pci_allocate_vc_save_buffers(dev);
> > > }
> > >
> > > diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> > > index e10cdec6c56e..92d8c92662a4 100644
> > > --- a/drivers/pci/pci.h
> > > +++ b/drivers/pci/pci.h
> > > @@ -562,11 +562,15 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev);
> > > void pcie_aspm_exit_link_state(struct pci_dev *pdev);
> > > void pcie_aspm_pm_state_change(struct pci_dev *pdev);
> > > void pcie_aspm_powersave_config_link(struct pci_dev *pdev);
> > > +void pci_save_aspm_l1ss_state(struct pci_dev *dev);
> > > +void pci_restore_aspm_l1ss_state(struct pci_dev *dev);
> > > #else
> > > static inline void pcie_aspm_init_link_state(struct pci_dev *pdev) { }
> > > static inline void pcie_aspm_exit_link_state(struct pci_dev *pdev) { }
> > > static inline void pcie_aspm_pm_state_change(struct pci_dev *pdev) { }
> > > static inline void pcie_aspm_powersave_config_link(struct pci_dev *pdev) { }
> > > +static inline void pci_save_aspm_l1ss_state(struct pci_dev *dev) { }
> > > +static inline void pci_restore_aspm_l1ss_state(struct pci_dev *dev) { }
> > > #endif
> > >
> > > #ifdef CONFIG_PCIE_ECRC
> > > diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
> > > index a96b7424c9bc..2c29fdd20059 100644
> > > --- a/drivers/pci/pcie/aspm.c
> > > +++ b/drivers/pci/pcie/aspm.c
> > > @@ -726,6 +726,50 @@ static void pcie_config_aspm_l1ss(struct pcie_link_state *link, u32 state)
> > > PCI_L1SS_CTL1_L1SS_MASK, val);
> > > }
> > >
> > > +void pci_save_aspm_l1ss_state(struct pci_dev *dev)
> > > +{
> > > + int aspm_l1ss;
> > > + struct pci_cap_saved_state *save_state;
> > > + u32 *cap;
> > > +
> > > + if (!pci_is_pcie(dev))
> > > + return;
> > > +
> > > + aspm_l1ss = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_L1SS);
> > > + if (!aspm_l1ss)
> > > + return;
> > > +
> > > + save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_L1SS);
> > > + if (!save_state)
> > > + return;
> > > +
> > > + cap = (u32 *)&save_state->cap.data[0];
> > > + pci_read_config_dword(dev, aspm_l1ss + PCI_L1SS_CTL2, cap++);
> > > + pci_read_config_dword(dev, aspm_l1ss + PCI_L1SS_CTL1, cap++);
> > > +}
> > > +
> > > +void pci_restore_aspm_l1ss_state(struct pci_dev *dev)
> > > +{
> > > + int aspm_l1ss;
> > > + struct pci_cap_saved_state *save_state;
> > > + u32 *cap;
> > > +
> > > + if (!pci_is_pcie(dev))
> > > + return;
> > > +
> > > + aspm_l1ss = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_L1SS);
> > > + if (!aspm_l1ss)
> > > + return;
> > > +
> > > + save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_L1SS);
> > > + if (!save_state)
> > > + return;
> > > +
> > > + cap = (u32 *)&save_state->cap.data[0];
> > > + pci_write_config_dword(dev, aspm_l1ss + PCI_L1SS_CTL2, *cap++);
> > > + pci_write_config_dword(dev, aspm_l1ss + PCI_L1SS_CTL1, *cap++);
> > > +}
> > > +
> > > static void pcie_config_aspm_dev(struct pci_dev *pdev, u32 val)
> > > {
> > > pcie_capability_clear_and_set_word(pdev, PCI_EXP_LNKCTL,
> > > --
> > > 2.17.1
> > >
Hi,
With this patch (and also mentioned
https://lore.kernel.org/all/20220509073639.2048236-1-kai.heng.feng@xxxxxxxxxxxxx/)
applied on 5.10 (chromeos-5.10) I am observing problems after
suspend/resume with my WiFi card - it looks like whole communication
via PCI fails. Attaching logs (dmesg, lspci -vvv before suspend/resume
and after) https://gist.github.com/semihalf-majczak-lukasz/fb36dfa2eff22911109dfb91ab0fc0e3
I played a little bit with this code and it looks like the
pci_write_config_dword() to the PCI_L1SS_CTL1 breaks it (don't know
why, not a PCI expert).
Best regards,
Lukasz