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    Subject[PATCH 4.14 022/117] PCI/ASPM: Allow re-enabling Clock PM
    Date
    From: Heiner Kallweit <hkallweit1@gmail.com>

    [ Upstream commit 35efea32b26f9aacc99bf07e0d2cdfba2028b099 ]

    Previously Clock PM could not be re-enabled after being disabled by
    pci_disable_link_state() because clkpm_capable was reset. Change this by
    adding a clkpm_disable field similar to aspm_disable.

    Link: https://lore.kernel.org/r/4e8a66db-7d53-4a66-c26c-f0037ffaa705@gmail.com
    Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
    Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/pci/pcie/aspm.c | 18 +++++++++++-------
    1 file changed, 11 insertions(+), 7 deletions(-)

    diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
    index 6f58767b5190f..400031622b761 100644
    --- a/drivers/pci/pcie/aspm.c
    +++ b/drivers/pci/pcie/aspm.c
    @@ -80,6 +80,7 @@ struct pcie_link_state {
    u32 clkpm_capable:1; /* Clock PM capable? */
    u32 clkpm_enabled:1; /* Current Clock PM state */
    u32 clkpm_default:1; /* Default Clock PM state by BIOS */
    + u32 clkpm_disable:1; /* Clock PM disabled */

    /* Exit latencies */
    struct aspm_latency latency_up; /* Upstream direction exit latency */
    @@ -177,8 +178,11 @@ static void pcie_set_clkpm_nocheck(struct pcie_link_state *link, int enable)

    static void pcie_set_clkpm(struct pcie_link_state *link, int enable)
    {
    - /* Don't enable Clock PM if the link is not Clock PM capable */
    - if (!link->clkpm_capable)
    + /*
    + * Don't enable Clock PM if the link is not Clock PM capable
    + * or Clock PM is disabled
    + */
    + if (!link->clkpm_capable || link->clkpm_disable)
    enable = 0;
    /* Need nothing if the specified equals to current state */
    if (link->clkpm_enabled == enable)
    @@ -208,7 +212,8 @@ static void pcie_clkpm_cap_init(struct pcie_link_state *link, int blacklist)
    }
    link->clkpm_enabled = enabled;
    link->clkpm_default = enabled;
    - link->clkpm_capable = (blacklist) ? 0 : capable;
    + link->clkpm_capable = capable;
    + link->clkpm_disable = blacklist ? 1 : 0;
    }

    static bool pcie_retrain_link(struct pcie_link_state *link)
    @@ -1052,10 +1057,9 @@ static void __pci_disable_link_state(struct pci_dev *pdev, int state, bool sem)
    link->aspm_disable |= ASPM_STATE_L1;
    pcie_config_aspm_link(link, policy_to_aspm_state(link));

    - if (state & PCIE_LINK_STATE_CLKPM) {
    - link->clkpm_capable = 0;
    - pcie_set_clkpm(link, 0);
    - }
    + if (state & PCIE_LINK_STATE_CLKPM)
    + link->clkpm_disable = 1;
    + pcie_set_clkpm(link, policy_to_clkpm_state(link));
    mutex_unlock(&aspm_lock);
    if (sem)
    up_read(&pci_bus_sem);
    --
    2.20.1


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