[SRU] [A/B/linux-oem] [PATCH 0/7] Fix Runtime PM for r8169

[Kai-Heng Feng]

Kai-Heng Feng <kai.heng.feng at canonical.com> wrote:

> BugLink: https://bugs.launchpad.net/bugs/1757422

For easier review, please check [1].

[1] https://github.com/khfeng/linux/tree/fix-r8169-rpm

>
> [Impact]
> r8169 stays in D0 even when no ethernet cable is plugged in. This drains
> lots of power (~3W). The tested laptop uses 5.5W when r8169 is in D0,
> 1.8W when r8169 is in D3. The power saved is substantial.
>
> [Fix]
> Improved rumtime PM logic to let the device gets suspended (D3) when the
> port is not in used and the link is down.
>
> [Test Case]
> The chip version is 8168h/8111h.
> Test when no ethernet gets plugged.
>
> Powertop shows power consumption is roughly 5.5W.
> lspci shows the device is in D0.
>
> With the patch,
> The power consumption is reduced to 1.8W.
> lspci shows the device is in D3, PME# is correctly enabled.
> Plug ethernet cable can corretly wake up the device.
> Unplug the cable, the device gets suspended to D3 correctly.
>
> [Regression Potential]
> Medium.
> - r8169 is so ubiquitous, with lots of different chip versions. It's
>   hard to test all of them.
> - PCI D3 needs system firmware (ACPI) support, this might hit some
>   plaform bugs.
> - the code is still in v4.16-rc*, so it's not well tested by end users.
>
> If it's too risky to merge this series into Artful, it should still get
> merged for Bionic, the power consumption reduction is significant.
>
> Daniel Drake (1):
>   r8169: only enable PCI wakeups when WOL is active
>
> Heiner Kallweit (6):
>   PCI: Add pcim_set_mwi(), a device-managed pci_set_mwi()
>   r8169: switch to device-managed functions in probe
>   r8169: remove netif_napi_del in probe error path
>   r8169: remove unneeded rpm ops in rtl_shutdown
>   r8169: improve runtime pm in rtl8169_check_link_status
>   r8169: improve runtime pm in general and suspend unused ports
>
>  drivers/net/ethernet/realtek/r8169.c | 131 ++++++++++-------------------------
>  drivers/pci/pci.c                    |  25 +++++++
>  include/linux/pci.h                  |   1 +
>  3 files changed, 62 insertions(+), 95 deletions(-)
>
> -- 
> 2.15.1
>
>
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