Re: [RFC] [PATCH net-next v5 2/3] r8169: Use PCIe ASPM status for NIC ASPM enablement

[Bjorn Helgaas <helgaas@kernel.org>]

On Thu, Sep 16, 2021 at 11:44:16PM +0800, Kai-Heng Feng wrote:
> Because ASPM control may not be granted by BIOS while ASPM is enabled,
> and ASPM can be enabled via sysfs, so use pcie_aspm_enabled() directly
> to check current ASPM enable status.
> 
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> ---
> v5:
>  - New patch.
> 
>  drivers/net/ethernet/realtek/r8169_main.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
> index 0199914440abc..6f1a9bec40c05 100644
> --- a/drivers/net/ethernet/realtek/r8169_main.c
> +++ b/drivers/net/ethernet/realtek/r8169_main.c
> @@ -622,7 +622,6 @@ struct rtl8169_private {
>  	} wk;
>  
>  	unsigned supports_gmii:1;
> -	unsigned aspm_manageable:1;
>  	dma_addr_t counters_phys_addr;
>  	struct rtl8169_counters *counters;
>  	struct rtl8169_tc_offsets tc_offset;
> @@ -2664,8 +2663,13 @@ static void rtl_enable_exit_l1(struct rtl8169_private *tp)
>  
>  static void rtl_hw_aspm_clkreq_enable(struct rtl8169_private *tp, bool enable)
>  {
> -	/* Don't enable ASPM in the chip if OS can't control ASPM */
> -	if (enable && tp->aspm_manageable) {
> +	struct pci_dev *pdev = tp->pci_dev;
> +
> +	/* Don't enable ASPM in the chip if PCIe ASPM isn't enabled */
> +	if (!pcie_aspm_enabled(pdev) && enable)
> +		return;

What happens when the user enables or disables ASPM via sysfs (see
https://git.kernel.org/linus/72ea91afbfb0)?

The driver is not going to know about that change.

> +	if (enable) {
>  		RTL_W8(tp, Config5, RTL_R8(tp, Config5) | ASPM_en);
>  		RTL_W8(tp, Config2, RTL_R8(tp, Config2) | ClkReqEn);
>  	} else {
> @@ -5272,8 +5276,7 @@ static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
>  	/* Disable ASPM L1 as that cause random device stop working
>  	 * problems as well as full system hangs for some PCIe devices users.
>  	 */
> -	rc = pci_disable_link_state(pdev, PCIE_LINK_STATE_L1);
> -	tp->aspm_manageable = !rc;
> +	pci_disable_link_state(pdev, PCIE_LINK_STATE_L1);
>  
>  	/* enable device (incl. PCI PM wakeup and hotplug setup) */
>  	rc = pcim_enable_device(pdev);
> -- 
> 2.32.0
>