Hi,
On 12/4/20 9:09 PM, Mario Limonciello wrote:
> commit e086ba2fccda ("e1000e: disable s0ix entry and exit flows for ME
> systems")
> disabled s0ix flows for systems that have various incarnations of the
> i219-LM ethernet controller. This was done because of some regressions
> caused by an earlier
> commit 632fbd5eb5b0e ("e1000e: fix S0ix flows for cable connected case")
> with i219-LM controller.
>
> Performing suspend to idle with these ethernet controllers requires a properly
> configured system. To make enabling such systems easier, this patch
> series allows determining if enabled and turning on using ethtool.
>
> The flows have also been confirmed to be configured correctly on Dell's
> Latitude
> and Precision CML systems containing the i219-LM controller, when the kernel
> also
> contains the fix for s0i3.2 entry previously submitted here and now part of
> this
> series.
> https://marc.info/?l=linux-netdev&m=160677194809564&w=2
>
> Patches 4 through 7 will turn the behavior on by default for some of Dell's
> CML and TGL systems.
First of all thank you for working on this.
I must say though that I don't like the approach taken here very
much.
This is not so much a criticism of this series as it is a criticism
of the earlier decision to simply disable s0ix on all devices
with the i219-LM + and active ME.
AFAIK there was a perfectly acceptable patch to workaround those
broken devices, which increased a timeout:
https://patchwork.ozlabs.org/project/intel-wired-lan/patch/20200323191639.48826-1-aaron...@canonical.com/
That patch was nacked because it increased the resume time
*on broken devices*.
So it seems to me that we have a simple choice here:
1. Longer resume time on devices with an improperly configured ME
2. Higher power-consumption on all non-buggy devices
Your patches 4-7 try to workaround 2. but IMHO those are just
bandaids for getting the initial priorities *very* wrong.
Instead of penalizing non-buggy devices with a higher power-consumption,
we should default to penalizing the buggy devices with a higher
resume time. And if it is decided that the higher resume time is
a worse problem then the higher power-consumption, then there
should be a list of broken devices and s0ix can be disabled on those.
The current allow-list approach is simply never going to work well
leading to too high power-consumption on countless devices.
This is going to be an endless game of whack-a-mole and as
such really is a bad idea.
A deny-list for broken devices is a much better approach, esp.
since missing devices on that list will still work fine, they
will just have a somewhat larger resume time.
So what needs to happen IMHO is:
1. Merge your fix from patch 1 of this set
2. Merge "e1000e: bump up timeout to wait when ME un-configure ULP mode"
3. Drop the e1000e_check_me check.
Then we also do not need the new "s0ix-enabled" ethertool flag
because we do not need userspace to work-around us doing the
wrong thing by default.
Note a while ago I had access to one of the devices having suspend/resume
issues caused by the S0ix support (a Lenovo Thinkpad X1 Carbon gen 7)
and I can confirm that the "e1000e: bump up timeout to wait when ME
un-configure ULP mode" patch fixes the suspend/resume problem without
any noticeable negative side-effects.
Regards,
Hans
>
> Changes from v2 to v3:
> - Correct some grammar and spelling issues caught by Bjorn H.
> * s/s0ix/S0ix/ in all commit messages
> * Fix a typo in commit message
> * Fix capitalization of proper nouns
> - Add more pre-release systems that pass
> - Re-order the series to add systems only at the end of the series
> - Add Fixes tag to a patch in series.
>
> Changes from v1 to v2:
> - Directly incorporate Vitaly's dependency patch in the series
> - Split out s0ix code into it's own file
> - Adjust from DMI matching to PCI subsystem vendor ID/device matching
> - Remove module parameter and sysfs, use ethtool flag instead.
> - Export s0ix flag to ethtool private flags
> - Include more people and lists directly in this submission chain.
>
> Mario Limonciello (6):
> e1000e: Move all S0ix related code into its own source file
> e1000e: Export S0ix flags to ethtool
> e1000e: Add Dell's Comet Lake systems into S0ix heuristics
> e1000e: Add more Dell CML systems into S0ix heuristics
> e1000e: Add Dell TGL desktop systems into S0ix heuristics
> e1000e: Add another Dell TGL notebook system into S0ix heuristics
>
> Vitaly Lifshits (1):
> e1000e: fix S0ix flow to allow S0i3.2 subset entry
>
> drivers/net/ethernet/intel/e1000e/Makefile | 2 +-
> drivers/net/ethernet/intel/e1000e/e1000.h | 4 +
> drivers/net/ethernet/intel/e1000e/ethtool.c | 40 +++
> drivers/net/ethernet/intel/e1000e/netdev.c | 272 +----------------
> drivers/net/ethernet/intel/e1000e/s0ix.c | 311 ++++++++++++++++++++
> 5 files changed, 361 insertions(+), 268 deletions(-)
> create mode 100644 drivers/net/ethernet/intel/e1000e/s0ix.c
>
> --
> 2.25.1
>
>
