Re: [Intel-wired-lan] [PATCH 2/3] e1000e: Make mei_me active when e1000e is in use

[Sasha Neftin <sasha.neftin@intel.com>]

On 7/12/2021 16:34, Kai-Heng Feng wrote:
> Many users report rather sluggish RX speed on TGP I219. Since
> "intel_idle.max_cstate=1" doesn't help, so it's not caused by deeper
> package C-state.
> 
> A workaround that always works is to make sure mei_me is runtime active
> when e1000e is in use.
> 
> The root cause is still unknown, but since many users are affected by
> the issue, implment the quirk in the driver as a temporary workaround.
Hello Kai-Heng,
First - thanks for the investigation of this problem. As I know CSME/AMT 
not POR on Linux and not supported. Recently we started add support for 
CSME/AMT none provisioned version (handshake with CSME in s0ix flow - 
only CSME with s0ix will support). It is not related to rx bandwidth 
problem.
I do not know how MEI driver affect 1Gbe driver - so, I would suggest to 
involve our CSME engineer (alexander.usyskin@intel.com) and try to 
investigate this problem.
Does this problem observed on Dell systems? As I heard no reproduction 
on Intel's RVP platform.
Another question: does disable mei_me runpm solve your problem?
> 
> Also adds mei_me as soft dependency to ensure the device link can be
> created if e1000e is in initramfs.
> 
> BugLink: https://bugs.launchpad.net/bugs/1927925
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=213377
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=213651
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> ---
>   drivers/net/ethernet/intel/e1000e/netdev.c | 26 ++++++++++++++++++++++
>   1 file changed, 26 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
> index 5835d6cf2f51..e63445a8ce12 100644
> --- a/drivers/net/ethernet/intel/e1000e/netdev.c
> +++ b/drivers/net/ethernet/intel/e1000e/netdev.c
> @@ -7317,6 +7317,27 @@ static const struct net_device_ops e1000e_netdev_ops = {
>   	.ndo_features_check	= passthru_features_check,
>   };
>   
> +static void e1000e_create_device_links(struct pci_dev *pdev)
> +{
> +	struct pci_dev *tgp_mei_me;
> +
> +	/* Find TGP mei_me devices and make e1000e power depend on mei_me */
> +	tgp_mei_me = pci_get_device(PCI_VENDOR_ID_INTEL, 0xa0e0, NULL);
> +	if (!tgp_mei_me) {
> +		tgp_mei_me = pci_get_device(PCI_VENDOR_ID_INTEL, 0x43e0, NULL);
> +		if (!tgp_mei_me)
> +			return;
> +	}
> +
> +	if (device_link_add(&pdev->dev, &tgp_mei_me->dev,
> +			    DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE |
> +			    DL_FLAG_AUTOREMOVE_CONSUMER))
> +		pci_info(pdev, "System and runtime PM depends on %s\n",
> +			 pci_name(tgp_mei_me));
> +
> +	pci_dev_put(tgp_mei_me);
> +}
> +
>   /**
>    * e1000_probe - Device Initialization Routine
>    * @pdev: PCI device information struct
> @@ -7645,6 +7666,9 @@ static int e1000_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>   	if (pci_dev_run_wake(pdev) && hw->mac.type != e1000_pch_cnp)
>   		pm_runtime_put_noidle(&pdev->dev);
>   
> +	if (hw->mac.type == e1000_pch_tgp)
> +		e1000e_create_device_links(pdev);
> +
>   	return 0;
>   
>   err_register:
> @@ -7917,6 +7941,8 @@ static void __exit e1000_exit_module(void)
>   }
>   module_exit(e1000_exit_module);
>   
> +/* Ensure device link can be created if e1000e is in the initramfs. */
> +MODULE_SOFTDEP("pre: mei_me");
>   MODULE_AUTHOR("Intel Corporation, <linux.nics@intel.com>");
>   MODULE_DESCRIPTION("Intel(R) PRO/1000 Network Driver");
>   MODULE_LICENSE("GPL v2");
> 
Thanks,Sasha