| Message ID | 1485891928-14573-1-git-send-email-okaya@codeaurora.org (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
> >When the operating system is booted with the default ASPM policy >(POLICY_DEFAULT), the current code is determining the ASPM policy >set up by the BIOS by querying the enable/disable states from ASPM >registers. > >In the case of hotplug removal, the ASPM registers get cleared by >calling the pcie_aspm_exit_link_state() function. > I see the same problem. So cherry-picked your change to resolve the problem on top of Linus mainline. >An insertion following hotplug removal reads incorrect policy as >ASPM disabled even though ASPM was enabled during boot. > >Adding a flag to the struct pci_dev and saving the power up policy >in the bridge to be reused during hotplug insertion. Bridge's enable >counter is used as a switch to determine when to use saved value. > >Signed-off-by: Sinan Kaya <okaya@codeaurora.org> >--- > drivers/pci/pcie/aspm.c | 21 +++++++++++++++++---- > include/linux/pci.h | 1 + > 2 files changed, 18 insertions(+), 4 deletions(-) > >diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c >index 17ac1dc..5cfcc6d 100644 >--- a/drivers/pci/pcie/aspm.c >+++ b/drivers/pci/pcie/aspm.c >@@ -338,8 +338,9 @@ static void pcie_aspm_check_latency(struct pci_dev *endpoint) > } > } > >-static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) >+static void pcie_aspm_cap_init(struct pci_dev *pdev, int blacklist) > { >+ struct pcie_link_state *link = pdev->link_state; > struct pci_dev *child, *parent = link->pdev; > struct pci_bus *linkbus = parent->subordinate; > struct aspm_register_info upreg, dwreg; >@@ -397,8 +398,20 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) > link->latency_up.l1 = calc_l1_latency(upreg.latency_encoding_l1); > link->latency_dw.l1 = calc_l1_latency(dwreg.latency_encoding_l1); > >- /* Save default state */ >- link->aspm_default = link->aspm_enabled; But, I am finding a problem with this change, if Policy is set to default, BIOS enables ASPM L1, but pcie_config_aspm_link() disables ASPM L1 due to link->aspm_enabled is different than link->aspm_default while called from pcie_aspm_init_link_state() during hotplug insertion. >+ /* >+ * Save default state from FW when enabling ASPM for the first time >+ * during boot by looking at the calculated link->aspm_enabled bits >+ * above and enable_cnt will be zero. >+ * >+ * If this path is getting called for the second/third time >+ * (enable_cnt will be non-zero). Assume that the current state of the >+ * ASPM registers may not necessarily match what FW asked us to do as >+ * in the case of hotplug insertion/removal. >+ */ >+ if (!atomic_read(&pdev->enable_cnt)) >+ pdev->aspm_default = link->aspm_default = link->aspm_enabled; >+ else >+ link->aspm_default = pdev->aspm_default; > > /* Setup initial capable state. Will be updated later */ > link->aspm_capable = link->aspm_support; >@@ -599,7 +612,7 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev) > * upstream links also because capable state of them can be > * update through pcie_aspm_cap_init(). > */ >- pcie_aspm_cap_init(link, blacklist); >+ pcie_aspm_cap_init(pdev, blacklist); > > /* Setup initial Clock PM state */ > pcie_clkpm_cap_init(link, blacklist); >diff --git a/include/linux/pci.h b/include/linux/pci.h >index e2d1a12..521f88c 100644 >--- a/include/linux/pci.h >+++ b/include/linux/pci.h >@@ -321,6 +321,7 @@ struct pci_dev { > > #ifdef CONFIG_PCIEASPM > struct pcie_link_state *link_state; /* ASPM link state */ >+ unsigned int aspm_default; /* ASPM policy set by BIOS */ > #endif > > pci_channel_state_t error_state; /* current connectivity state */ >-- >1.9.1 > >-- >To unsubscribe from this list: send the line "unsubscribe linux-pci" in >the body of a message to majordomo@vger.kernel.org >More majordomo info at http://vger.kernel.org/majordomo-info.html Intel Deutschland GmbH Registered Address: Am Campeon 10-12, 85579 Neubiberg, Germany Tel: +49 89 99 8853-0, www.intel.de Managing Directors: Christin Eisenschmid, Christian Lamprechter Chairperson of the Supervisory Board: Nicole Lau Registered Office: Munich Commercial Register: Amtsgericht Muenchen HRB 186928
On 2/28/2017 6:03 AM, Patel, Mayurkumar wrote: >> - /* Save default state */ >> - link->aspm_default = link->aspm_enabled; > But, I am finding a problem with this change, if Policy is set to default, > BIOS enables ASPM L1, but pcie_config_aspm_link() disables ASPM L1 > due to link->aspm_enabled is different than link->aspm_default while > called from pcie_aspm_init_link_state() during hotplug insertion. > Thanks for testing. I think it means the enable count logic I put below is not working. I was trying to figure out when to use saved values vs. the values in registers by looking at the enable_cnt. enable_cnt is 0 during boot on my system. The enable_cnt should have been non-zero following an insertion following remove and default and enabled values should have been identical. Can you print out the values of pdev->aspm_default, link->aspm_default, and link->aspm_enabled in this function along with atomic_read(&pdev->enable_cnt)? > >> + /* >> + * Save default state from FW when enabling ASPM for the first time >> + * during boot by looking at the calculated link->aspm_enabled bits >> + * above and enable_cnt will be zero. >> + * >> + * If this path is getting called for the second/third time >> + * (enable_cnt will be non-zero). Assume that the current state of the >> + * ASPM registers may not necessarily match what FW asked us to do as >> + * in the case of hotplug insertion/removal. >> + */ >> + if (!atomic_read(&pdev->enable_cnt)) >> + pdev->aspm_default = link->aspm_default = link->aspm_enabled; >> + else >> + link->aspm_default = pdev->aspm_default;
> >On 2/28/2017 6:03 AM, Patel, Mayurkumar wrote: >>> - /* Save default state */ >>> - link->aspm_default = link->aspm_enabled; >> But, I am finding a problem with this change, if Policy is set to default, >> BIOS enables ASPM L1, but pcie_config_aspm_link() disables ASPM L1 >> due to link->aspm_enabled is different than link->aspm_default while >> called from pcie_aspm_init_link_state() during hotplug insertion. >> > >Thanks for testing. I think it means the enable count logic I put below >is not working. Yes I believe so. > >I was trying to figure out when to use saved values vs. the values in >registers by looking at the enable_cnt. >enable_cnt is 0 during boot on my system. enable_cnt for the root port on my system is set to 1 for "root port" already without saving any ASPM related settings. > >The enable_cnt should have been non-zero following an insertion following >remove and default and enabled values should have been identical. > pcie_aspm_init_link_state() is called on the "root port" from hotplug routine when I plug in PCIE Endpoint. And in my case root port "enable_cnt" is already set to 1 because of root port driver probed already. So link->aspm_default by default always sets to pdev->aspm_default which is 0 as it was never set to BIOS values before. I will continue dig in further to see how the "root port" probe gets triggered and why it does not call pcie_aspm_init_link_state() to store aspm policy before "enable_cnt" becomes 1 for it. >Can you print out the values of pdev->aspm_default, link->aspm_default, >and link->aspm_enabled in this function along with atomic_read(&pdev->enable_cnt)? > >> Yes. Also printed link control register(lnkctl) set by BIOS for upstream port and downstream port Which gets disabled afterwards due to the link->aspm_default is 0. The prints are in pcie_aspm_cap_init() Function. [ 199.287732] pci 0000:03:00.0: reg 0x10: [mem 0x00000000-0x00000fff 64bit] [ 199.287748] pci 0000:03:00.0: reg 0x18: [mem 0x00000000-0x000000ff 64bit] [ 199.287864] pci 0000:03:00.0: PME# supported from D0 D3hot D3cold [ 199.288000] pci 0000:03:00.0: System wakeup disabled by ACPI [ 199.299868] upreg lnkcap 00000003 lnkctl=00000042 [ 199.299996] dwreg lnkcap 00000002 lnkctl=00000142 [ 199.300076] pdev_aspm_default: 0x00000000 link_aspm_default: 0x00000000 aspm_enabled: 0x00000004 enable_cnt: 0x00000001 [ 199.300402] pci 0000:03:00.0: BAR 0: assigned [mem 0xaa000000-0xaa000fff 64bit] [ 199.300413] pci 0000:03:00.0: BAR 2: assigned [mem 0xaa001000-0xaa0010ff 64bit] >>> + /* >>> + * Save default state from FW when enabling ASPM for the first time >>> + * during boot by looking at the calculated link->aspm_enabled bits >>> + * above and enable_cnt will be zero. >>> + * >>> + * If this path is getting called for the second/third time >>> + * (enable_cnt will be non-zero). Assume that the current state of the >>> + * ASPM registers may not necessarily match what FW asked us to do as >>> + * in the case of hotplug insertion/removal. >>> + */ >>> + if (!atomic_read(&pdev->enable_cnt)) >>> + pdev->aspm_default = link->aspm_default = link->aspm_enabled; >>> + else >>> + link->aspm_default = pdev->aspm_default; > > >-- >Sinan Kaya >Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. >Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project. Intel Deutschland GmbH Registered Address: Am Campeon 10-12, 85579 Neubiberg, Germany Tel: +49 89 99 8853-0, www.intel.de Managing Directors: Christin Eisenschmid, Christian Lamprechter Chairperson of the Supervisory Board: Nicole Lau Registered Office: Munich Commercial Register: Amtsgericht Muenchen HRB 186928
Hi Bjorn, On 2/28/2017 1:57 PM, Patel, Mayurkumar wrote: >> I was trying to figure out when to use saved values vs. the values in >> registers by looking at the enable_cnt. >> enable_cnt is 0 during boot on my system. > enable_cnt for the root port on my system is set to 1 for "root port" already without saving > any ASPM related settings. > > What would be the best way to figure out when to save power-on values from the registers?
> >Hi Bjorn, > >On 2/28/2017 1:57 PM, Patel, Mayurkumar wrote: >>> I was trying to figure out when to use saved values vs. the values in >>> registers by looking at the enable_cnt. >>> enable_cnt is 0 during boot on my system. >> enable_cnt for the root port on my system is set to 1 for "root port" already without saving >> any ASPM related settings. >> >> > >What would be the best way to figure out when to save power-on values from >the registers? > So in my case, pci_enable_device() for root port is called from pcie_port_device_register() at the boot time which Is called from pcie_portdrv_probe() function which does not call pcie_aspm_init_link_state() but Increment's enable_cnt field. When the Endpoint get plugged in, pcie_aspm_init_link_state() is called from hotplug routine on "Root port" but due to enable_cnt is already incremented we do not set right policy and aspm gets disabled by aspm driver. Shall we introduce new atomic variable along with aspm_default in struct pci_dev and increment it in when called first time pcie_aspm_init_link_state() to save power-on values ( I have tested it locally, if you think could be good approach I can upload the diffs) because enable_cnt in pci_enable_device() can be triggered from multiple places at boot time so it might not be safe to use it? or adding pcie_aspm_init_link_state() in pcie_port_device_register() for ports before calling pci_enable_device() although I am not sure whether it's the right approach and that would work for all the devices! @Kaya/Bjorn: Do you have any other suggestions or Could you also please help by comment what would make sense? >-- >Sinan Kaya >Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. >Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project. Intel Deutschland GmbH Registered Address: Am Campeon 10-12, 85579 Neubiberg, Germany Tel: +49 89 99 8853-0, www.intel.de Managing Directors: Christin Eisenschmid, Christian Lamprechter Chairperson of the Supervisory Board: Nicole Lau Registered Office: Munich Commercial Register: Amtsgericht Muenchen HRB 186928
Hi Mayurkumar On 3/2/2017 11:05 AM, Patel, Mayurkumar wrote: >> >> Hi Bjorn, >> >> On 2/28/2017 1:57 PM, Patel, Mayurkumar wrote: >>>> I was trying to figure out when to use saved values vs. the values in >>>> registers by looking at the enable_cnt. >>>> enable_cnt is 0 during boot on my system. >>> enable_cnt for the root port on my system is set to 1 for "root port" already without saving >>> any ASPM related settings. >>> >>> >> >> What would be the best way to figure out when to save power-on values from >> the registers? >> > > I can upload the diffs) because enable_cnt in pci_enable_device() can be triggered > from multiple places at boot time so it might not be safe to use it? Go ahead and share your diff. It doesn't hurt to look at other alternatives. > > @Kaya/Bjorn: Do you have any other suggestions or Could you also please help by comment what would make sense? > > >> -- >> Sinan Kaya >> Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. >> Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project. > Intel Deutschland GmbH > Registered Address: Am Campeon 10-12, 85579 Neubiberg, Germany > Tel: +49 89 99 8853-0, www.intel.de > Managing Directors: Christin Eisenschmid, Christian Lamprechter > Chairperson of the Supervisory Board: Nicole Lau > Registered Office: Munich > Commercial Register: Amtsgericht Muenchen HRB 186928 > >
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index 17ac1dc..5cfcc6d 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -338,8 +338,9 @@ static void pcie_aspm_check_latency(struct pci_dev *endpoint) } } -static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) +static void pcie_aspm_cap_init(struct pci_dev *pdev, int blacklist) { + struct pcie_link_state *link = pdev->link_state; struct pci_dev *child, *parent = link->pdev; struct pci_bus *linkbus = parent->subordinate; struct aspm_register_info upreg, dwreg; @@ -397,8 +398,20 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) link->latency_up.l1 = calc_l1_latency(upreg.latency_encoding_l1); link->latency_dw.l1 = calc_l1_latency(dwreg.latency_encoding_l1); - /* Save default state */ - link->aspm_default = link->aspm_enabled; + /* + * Save default state from FW when enabling ASPM for the first time + * during boot by looking at the calculated link->aspm_enabled bits + * above and enable_cnt will be zero. + * + * If this path is getting called for the second/third time + * (enable_cnt will be non-zero). Assume that the current state of the + * ASPM registers may not necessarily match what FW asked us to do as + * in the case of hotplug insertion/removal. + */ + if (!atomic_read(&pdev->enable_cnt)) + pdev->aspm_default = link->aspm_default = link->aspm_enabled; + else + link->aspm_default = pdev->aspm_default; /* Setup initial capable state. Will be updated later */ link->aspm_capable = link->aspm_support; @@ -599,7 +612,7 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev) * upstream links also because capable state of them can be * update through pcie_aspm_cap_init(). */ - pcie_aspm_cap_init(link, blacklist); + pcie_aspm_cap_init(pdev, blacklist); /* Setup initial Clock PM state */ pcie_clkpm_cap_init(link, blacklist); diff --git a/include/linux/pci.h b/include/linux/pci.h index e2d1a12..521f88c 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -321,6 +321,7 @@ struct pci_dev { #ifdef CONFIG_PCIEASPM struct pcie_link_state *link_state; /* ASPM link state */ + unsigned int aspm_default; /* ASPM policy set by BIOS */ #endif pci_channel_state_t error_state; /* current connectivity state */
When the operating system is booted with the default ASPM policy (POLICY_DEFAULT), the current code is determining the ASPM policy set up by the BIOS by querying the enable/disable states from ASPM registers. In the case of hotplug removal, the ASPM registers get cleared by calling the pcie_aspm_exit_link_state() function. An insertion following hotplug removal reads incorrect policy as ASPM disabled even though ASPM was enabled during boot. Adding a flag to the struct pci_dev and saving the power up policy in the bridge to be reused during hotplug insertion. Bridge's enable counter is used as a switch to determine when to use saved value. Signed-off-by: Sinan Kaya <okaya@codeaurora.org> --- drivers/pci/pcie/aspm.c | 21 +++++++++++++++++---- include/linux/pci.h | 1 + 2 files changed, 18 insertions(+), 4 deletions(-)