>
>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@xxxxxxxxxxxxxx>
>---
> 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@xxxxxxxxxxxxxxx
>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
--
To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
