* Re: [PATCH v3 3/3] PCI/ASPM: Fix L1SS parameters & only enable supported features when enable link state
2024-02-07 11:18 [PATCH v3 3/3] PCI/ASPM: Fix L1SS parameters & only enable supported features when enable link state Jian-Hong Pan
@ 2024-02-07 12:54 ` Ilpo Järvinen
2024-02-07 16:02 ` David E. Box
2024-02-07 17:19 ` Kuppuswamy Sathyanarayanan
2 siblings, 0 replies; 5+ messages in thread
From: Ilpo Järvinen @ 2024-02-07 12:54 UTC (permalink / raw)
To: Jian-Hong Pan
Cc: Bjorn Helgaas, Johan Hovold, David Box, Mika Westerberg,
Nirmal Patel, Jonathan Derrick, linux-pci, LKML, linux
On Wed, 7 Feb 2024, Jian-Hong Pan wrote:
> The original __pci_enable_link_state() configs the links directly without:
> * Check the L1 substates features which are supported, or not
> * Calculate & program related parameters for L1.2, such as T_POWER_ON,
> Common_Mode_Restore_Time, and LTR_L1.2_THRESHOLD
>
> This leads some supported L1 PM substates of the link between VMD remapped
> PCIe Root Port and NVMe get wrong configs when a caller tries to enabled
> them.
>
> Here is a failed example on ASUS B1400CEAE with enabled VMD:
>
> 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
>
> This patch initializes the link's L1 PM substates to get the supported
> features and programs relating paramters, if some of them are going to be
> enabled in __pci_enable_link_state(). Then, enables the L1 PM substates if
> the caller intends to enable them and they are supported.
>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=218394
> Signed-off-by: Jian-Hong Pan <jhp@endlessos.org>
> ---
> v2:
> - Prepare the PCIe LTR parameters before enable L1 Substates
>
> v3:
> - Only enable supported features for the L1 Substates part
>
> drivers/pci/pcie/aspm.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
> index a39d2ee744cb..c866971cae70 100644
> --- a/drivers/pci/pcie/aspm.c
> +++ b/drivers/pci/pcie/aspm.c
> @@ -1389,14 +1389,16 @@ static int __pci_enable_link_state(struct pci_dev *pdev, int state, bool locked)
> link->aspm_default |= ASPM_STATE_L0S;
> if (state & PCIE_LINK_STATE_L1)
> link->aspm_default |= ASPM_STATE_L1;
> - /* L1 PM substates require L1 */
> - if (state & PCIE_LINK_STATE_L1_1)
> + if (state & ASPM_STATE_L1_2_MASK)
> + aspm_l1ss_init(link);
Your commit message didn't explain why you need to add this call here, why
isn't the existing call to aspm_l1ss_init() enough to initialize what is
needed?
> + /* L1 PM substates require L1 and should be in supported list */
> + if (state & link->aspm_support & PCIE_LINK_STATE_L1_1)
> link->aspm_default |= ASPM_STATE_L1_1 | ASPM_STATE_L1;
> - if (state & PCIE_LINK_STATE_L1_2)
> + if (state & link->aspm_support & PCIE_LINK_STATE_L1_2)
> link->aspm_default |= ASPM_STATE_L1_2 | ASPM_STATE_L1;
> - if (state & PCIE_LINK_STATE_L1_1_PCIPM)
> + if (state & link->aspm_support & PCIE_LINK_STATE_L1_1_PCIPM)
> link->aspm_default |= ASPM_STATE_L1_1_PCIPM | ASPM_STATE_L1;
> - if (state & PCIE_LINK_STATE_L1_2_PCIPM)
> + if (state & link->aspm_support & PCIE_LINK_STATE_L1_2_PCIPM)
> link->aspm_default |= ASPM_STATE_L1_2_PCIPM | ASPM_STATE_L1;
It would be simpler and cleaner to just AND once with link->aspm_support
to clear unsupported bits from state rather than doing it on every line
like that.
--
i.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v3 3/3] PCI/ASPM: Fix L1SS parameters & only enable supported features when enable link state
2024-02-07 11:18 [PATCH v3 3/3] PCI/ASPM: Fix L1SS parameters & only enable supported features when enable link state Jian-Hong Pan
2024-02-07 12:54 ` Ilpo Järvinen
@ 2024-02-07 16:02 ` David E. Box
2024-02-16 3:13 ` Jian-Hong Pan
2024-02-07 17:19 ` Kuppuswamy Sathyanarayanan
2 siblings, 1 reply; 5+ messages in thread
From: David E. Box @ 2024-02-07 16:02 UTC (permalink / raw)
To: Jian-Hong Pan, Bjorn Helgaas, Johan Hovold, Ilpo Järvinen
Cc: Mika Westerberg, Nirmal Patel, Jonathan Derrick, linux-pci,
linux-kernel, linux
On Wed, 2024-02-07 at 19:18 +0800, Jian-Hong Pan wrote:
> The original __pci_enable_link_state() configs the links directly without:
> * Check the L1 substates features which are supported, or not
> * Calculate & program related parameters for L1.2, such as T_POWER_ON,
> Common_Mode_Restore_Time, and LTR_L1.2_THRESHOLD
>
> This leads some supported L1 PM substates of the link between VMD remapped
> PCIe Root Port and NVMe get wrong configs when a caller tries to enabled
> them.
>
> Here is a failed example on ASUS B1400CEAE with enabled VMD:
>
> 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
>
> This patch initializes the link's L1 PM substates to get the supported
> features and programs relating paramters, if some of them are going to be
> enabled in __pci_enable_link_state(). Then, enables the L1 PM substates if
> the caller intends to enable them and they are supported.
>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=218394
> Signed-off-by: Jian-Hong Pan <jhp@endlessos.org>
> ---
> v2:
> - Prepare the PCIe LTR parameters before enable L1 Substates
>
> v3:
> - Only enable supported features for the L1 Substates part
>
> drivers/pci/pcie/aspm.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
> index a39d2ee744cb..c866971cae70 100644
> --- a/drivers/pci/pcie/aspm.c
> +++ b/drivers/pci/pcie/aspm.c
> @@ -1389,14 +1389,16 @@ static int __pci_enable_link_state(struct pci_dev
> *pdev, int state, bool locked)
> link->aspm_default |= ASPM_STATE_L0S;
> if (state & PCIE_LINK_STATE_L1)
> link->aspm_default |= ASPM_STATE_L1;
> - /* L1 PM substates require L1 */
> - if (state & PCIE_LINK_STATE_L1_1)
> + if (state & ASPM_STATE_L1_2_MASK)
> + aspm_l1ss_init(link);
This mixes ASPM_STATE flags with PCIE_LINK_STATE register mapping. This may work
but I don't know if it's intended to. Rather do,
if (link->default & ASPM_STATE_L1_2_MASK)
after collecting all of the states to be enabled.
I understand that you are calling aspm_l1ss_init() to do the L1.2 calculations
but it does more than this that you don't need. Maybe it would be more
appropriate to call aspm_calc_l12_info() directly through an additional function
that finds the parent and determines both ends of the link support L1SS.
> + /* L1 PM substates require L1 and should be in supported list */
> + if (state & link->aspm_support & PCIE_LINK_STATE_L1_1)
> link->aspm_default |= ASPM_STATE_L1_1 | ASPM_STATE_L1;
> - if (state & PCIE_LINK_STATE_L1_2)
> + if (state & link->aspm_support & PCIE_LINK_STATE_L1_2)
> link->aspm_default |= ASPM_STATE_L1_2 | ASPM_STATE_L1;
> - if (state & PCIE_LINK_STATE_L1_1_PCIPM)
> + if (state & link->aspm_support & PCIE_LINK_STATE_L1_1_PCIPM)
> link->aspm_default |= ASPM_STATE_L1_1_PCIPM | ASPM_STATE_L1;
> - if (state & PCIE_LINK_STATE_L1_2_PCIPM)
> + if (state & link->aspm_support & PCIE_LINK_STATE_L1_2_PCIPM)
> link->aspm_default |= ASPM_STATE_L1_2_PCIPM | ASPM_STATE_L1;
> pcie_config_aspm_link(link, policy_to_aspm_state(link));
>
I don't think these changes are necessary. pcie_config_aspm_link() already
checks link->aspm_capable which was initialized from link->aspm_support.
David
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH v3 3/3] PCI/ASPM: Fix L1SS parameters & only enable supported features when enable link state
2024-02-07 16:02 ` David E. Box
@ 2024-02-16 3:13 ` Jian-Hong Pan
0 siblings, 0 replies; 5+ messages in thread
From: Jian-Hong Pan @ 2024-02-16 3:13 UTC (permalink / raw)
To: david.e.box
Cc: Bjorn Helgaas, Johan Hovold, Ilpo Järvinen, Mika Westerberg,
Nirmal Patel, Jonathan Derrick, Kuppuswamy Sathyanarayanan,
linux-pci, linux-kernel, linux
David E. Box <david.e.box@linux.intel.com> 於 2024年2月8日 週四 上午12:02寫道：
>
> On Wed, 2024-02-07 at 19:18 +0800, Jian-Hong Pan wrote:
> > The original __pci_enable_link_state() configs the links directly without:
> > * Check the L1 substates features which are supported, or not
> > * Calculate & program related parameters for L1.2, such as T_POWER_ON,
> > Common_Mode_Restore_Time, and LTR_L1.2_THRESHOLD
> >
> > This leads some supported L1 PM substates of the link between VMD remapped
> > PCIe Root Port and NVMe get wrong configs when a caller tries to enabled
> > them.
> >
> > Here is a failed example on ASUS B1400CEAE with enabled VMD:
> >
> > 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
> >
> > This patch initializes the link's L1 PM substates to get the supported
> > features and programs relating paramters, if some of them are going to be
> > enabled in __pci_enable_link_state(). Then, enables the L1 PM substates if
> > the caller intends to enable them and they are supported.
> >
> > Link: https://bugzilla.kernel.org/show_bug.cgi?id=218394
> > Signed-off-by: Jian-Hong Pan <jhp@endlessos.org>
> > ---
> > v2:
> > - Prepare the PCIe LTR parameters before enable L1 Substates
> >
> > v3:
> > - Only enable supported features for the L1 Substates part
> >
> > drivers/pci/pcie/aspm.c | 12 +++++++-----
> > 1 file changed, 7 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
> > index a39d2ee744cb..c866971cae70 100644
> > --- a/drivers/pci/pcie/aspm.c
> > +++ b/drivers/pci/pcie/aspm.c
> > @@ -1389,14 +1389,16 @@ static int __pci_enable_link_state(struct pci_dev
> > *pdev, int state, bool locked)
> > link->aspm_default |= ASPM_STATE_L0S;
> > if (state & PCIE_LINK_STATE_L1)
> > link->aspm_default |= ASPM_STATE_L1;
> > - /* L1 PM substates require L1 */
> > - if (state & PCIE_LINK_STATE_L1_1)
> > + if (state & ASPM_STATE_L1_2_MASK)
> > + aspm_l1ss_init(link);
>
> This mixes ASPM_STATE flags with PCIE_LINK_STATE register mapping. This may work
> but I don't know if it's intended to. Rather do,
>
> if (link->default & ASPM_STATE_L1_2_MASK)
>
> after collecting all of the states to be enabled.
>
> I understand that you are calling aspm_l1ss_init() to do the L1.2 calculations
> but it does more than this that you don't need. Maybe it would be more
> appropriate to call aspm_calc_l12_info() directly through an additional function
> that finds the parent and determines both ends of the link support L1SS.
After think & check twice, focusing on fixing the L1.2 parameters makes sense.
I am preparing a new patch. Thanks!
Jian-Hong Pan
> > + /* L1 PM substates require L1 and should be in supported list */
> > + if (state & link->aspm_support & PCIE_LINK_STATE_L1_1)
> > link->aspm_default |= ASPM_STATE_L1_1 | ASPM_STATE_L1;
> > - if (state & PCIE_LINK_STATE_L1_2)
> > + if (state & link->aspm_support & PCIE_LINK_STATE_L1_2)
> > link->aspm_default |= ASPM_STATE_L1_2 | ASPM_STATE_L1;
> > - if (state & PCIE_LINK_STATE_L1_1_PCIPM)
> > + if (state & link->aspm_support & PCIE_LINK_STATE_L1_1_PCIPM)
> > link->aspm_default |= ASPM_STATE_L1_1_PCIPM | ASPM_STATE_L1;
> > - if (state & PCIE_LINK_STATE_L1_2_PCIPM)
> > + if (state & link->aspm_support & PCIE_LINK_STATE_L1_2_PCIPM)
> > link->aspm_default |= ASPM_STATE_L1_2_PCIPM | ASPM_STATE_L1;
> > pcie_config_aspm_link(link, policy_to_aspm_state(link));
> >
>
> I don't think these changes are necessary. pcie_config_aspm_link() already
> checks link->aspm_capable which was initialized from link->aspm_support.
>
> David
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v3 3/3] PCI/ASPM: Fix L1SS parameters & only enable supported features when enable link state
2024-02-07 11:18 [PATCH v3 3/3] PCI/ASPM: Fix L1SS parameters & only enable supported features when enable link state Jian-Hong Pan
2024-02-07 12:54 ` Ilpo Järvinen
2024-02-07 16:02 ` David E. Box
@ 2024-02-07 17:19 ` Kuppuswamy Sathyanarayanan
2 siblings, 0 replies; 5+ messages in thread
From: Kuppuswamy Sathyanarayanan @ 2024-02-07 17:19 UTC (permalink / raw)
To: Jian-Hong Pan, Bjorn Helgaas, Johan Hovold, Ilpo Järvinen,
David Box
Cc: Mika Westerberg, Nirmal Patel, Jonathan Derrick, linux-pci,
linux-kernel, linux
On 2/7/24 3:18 AM, Jian-Hong Pan wrote:
> The original __pci_enable_link_state() configs the links directly without:
Since you are referring to the current version of this function, just start
with "Currently, "
> * Check the L1 substates features which are supported, or not
> * Calculate & program related parameters for L1.2, such as T_POWER_ON,
> Common_Mode_Restore_Time, and LTR_L1.2_THRESHOLD
>
> This leads some supported L1 PM substates of the link between VMD remapped
> PCIe Root Port and NVMe get wrong configs when a caller tries to enabled
> them.
>
> Here is a failed example on ASUS B1400CEAE with enabled VMD:
>
> 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
>
> This patch initializes the link's L1 PM substates to get the supported
> features and programs relating paramters, if some of them are going to be
> enabled in __pci_enable_link_state(). Then, enables the L1 PM substates if
> the caller intends to enable them and they are supported.
>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=218394
> Signed-off-by: Jian-Hong Pan <jhp@endlessos.org>
> ---
> v2:
> - Prepare the PCIe LTR parameters before enable L1 Substates
>
> v3:
> - Only enable supported features for the L1 Substates part
>
> drivers/pci/pcie/aspm.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
> index a39d2ee744cb..c866971cae70 100644
> --- a/drivers/pci/pcie/aspm.c
> +++ b/drivers/pci/pcie/aspm.c
> @@ -1389,14 +1389,16 @@ static int __pci_enable_link_state(struct pci_dev *pdev, int state, bool locked)
> link->aspm_default |= ASPM_STATE_L0S;
> if (state & PCIE_LINK_STATE_L1)
> link->aspm_default |= ASPM_STATE_L1;
> - /* L1 PM substates require L1 */
> - if (state & PCIE_LINK_STATE_L1_1)
> + if (state & ASPM_STATE_L1_2_MASK)
> + aspm_l1ss_init(link);
This is a new change. Explain why you are doing it?
> + /* L1 PM substates require L1 and should be in supported list */
> + if (state & link->aspm_support & PCIE_LINK_STATE_L1_1)
> link->aspm_default |= ASPM_STATE_L1_1 | ASPM_STATE_L1;
> - if (state & PCIE_LINK_STATE_L1_2)
> + if (state & link->aspm_support & PCIE_LINK_STATE_L1_2)
> link->aspm_default |= ASPM_STATE_L1_2 | ASPM_STATE_L1;
> - if (state & PCIE_LINK_STATE_L1_1_PCIPM)
> + if (state & link->aspm_support & PCIE_LINK_STATE_L1_1_PCIPM)
> link->aspm_default |= ASPM_STATE_L1_1_PCIPM | ASPM_STATE_L1;
> - if (state & PCIE_LINK_STATE_L1_2_PCIPM)
> + if (state & link->aspm_support & PCIE_LINK_STATE_L1_2_PCIPM)
> link->aspm_default |= ASPM_STATE_L1_2_PCIPM | ASPM_STATE_L1;
> pcie_config_aspm_link(link, policy_to_aspm_state(link));
>
--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer
^ permalink raw reply [flat|nested] 5+ messages in thread