From: Lukas Wunner lukas@wunner.de
stable inclusion from stable-v6.6.3 commit 0763bcef474d2a520def66900455e950127b4eff category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8LBQP
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 70b70a4307cccebe91388337b1c85735ce4de6ff upstream.
struct pci_dev contains two flags which govern whether the device may suspend to D3cold:
* no_d3cold provides an opt-out for drivers (e.g. if a device is known to not wake from D3cold)
* d3cold_allowed provides an opt-out for user space (default is true, user space may set to false)
Since commit 9d26d3a8f1b0 ("PCI: Put PCIe ports into D3 during suspend"), the user space setting overwrites the driver setting. Essentially user space is trusted to know better than the driver whether D3cold is working.
That feels unsafe and wrong. Assume that the change was introduced inadvertently and do not overwrite no_d3cold when d3cold_allowed is modified. Instead, consider d3cold_allowed in addition to no_d3cold when choosing a suspend state for the device.
That way, user space may opt out of D3cold if the driver hasn't, but it may no longer force an opt in if the driver has opted out.
Fixes: 9d26d3a8f1b0 ("PCI: Put PCIe ports into D3 during suspend") Link: https://lore.kernel.org/r/b8a7f4af2b73f6b506ad8ddee59d747cbf834606.169502536... Signed-off-by: Lukas Wunner lukas@wunner.de Signed-off-by: Bjorn Helgaas bhelgaas@google.com Reviewed-by: Mika Westerberg mika.westerberg@linux.intel.com Reviewed-by: Mario Limonciello mario.limonciello@amd.com Cc: stable@vger.kernel.org # v4.8+ Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- drivers/pci/pci-acpi.c | 2 +- drivers/pci/pci-sysfs.c | 5 +---- 2 files changed, 2 insertions(+), 5 deletions(-)
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c index a05350a4e49c..05b7357bd258 100644 --- a/drivers/pci/pci-acpi.c +++ b/drivers/pci/pci-acpi.c @@ -911,7 +911,7 @@ pci_power_t acpi_pci_choose_state(struct pci_dev *pdev) { int acpi_state, d_max;
- if (pdev->no_d3cold) + if (pdev->no_d3cold || !pdev->d3cold_allowed) d_max = ACPI_STATE_D3_HOT; else d_max = ACPI_STATE_D3_COLD; diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 5a6241044c3c..3317b9354716 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -529,10 +529,7 @@ static ssize_t d3cold_allowed_store(struct device *dev, return -EINVAL;
pdev->d3cold_allowed = !!val; - if (pdev->d3cold_allowed) - pci_d3cold_enable(pdev); - else - pci_d3cold_disable(pdev); + pci_bridge_d3_update(pdev);
pm_runtime_resume(dev);