Lorenzo Bianconi <lorenzo@xxxxxxxxxx> writes:
> On same device (e.g. U7612E-H1) PCIE_ASPM causes continuous mcu hangs and
> instability and so let's disable PCIE_ASPM by default. This patch has
> been successfully tested on U7612E-H1 mini-pice card
>
> Signed-off-by: Felix Fietkau <nbd@xxxxxxxx>
> Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
[...]
> +void mt76_mmio_disable_aspm(struct pci_dev *pdev)
> +{
> + struct pci_dev *parent = pdev->bus->self;
> + u16 aspm_conf, parent_aspm_conf = 0;
> +
> + pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &aspm_conf);
> + aspm_conf &= PCI_EXP_LNKCTL_ASPMC;
> + if (parent) {
> + pcie_capability_read_word(parent, PCI_EXP_LNKCTL,
> + &parent_aspm_conf);
> + parent_aspm_conf &= PCI_EXP_LNKCTL_ASPMC;
> + }
> +
> + if (!aspm_conf && (!parent || !parent_aspm_conf)) {
> + /* aspm already disabled */
> + return;
> + }
> +
> + dev_info(&pdev->dev, "disabling ASPM %s %s\n",
> + (aspm_conf & PCI_EXP_LNKCTL_ASPM_L0S) ? "L0s" : "",
> + (aspm_conf & PCI_EXP_LNKCTL_ASPM_L1) ? "L1" : "");
> +
> +#ifdef CONFIG_PCIEASPM
> + pci_disable_link_state(pdev, aspm_conf);
> +
> + /* Double-check ASPM control. If not disabled by the above, the
> + * BIOS is preventing that from happening (or CONFIG_PCIEASPM is
> + * not enabled); override by writing PCI config space directly.
> + */
> + pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &aspm_conf);
> + if (!(aspm_conf & PCI_EXP_LNKCTL_ASPMC))
> + return;
> +#endif /* CONFIG_PCIEASPM */
A minor comment, but 'if IS_ENABLED(CONFIG_PCIEASPM)' is preferred over
#ifdef. Better compiler coverage and so on.
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