[PATCH v2 0/1][SRU][OEM-OSP1-B] UBUNTU: SAUCE: pci: Speed up the process of s3 resume

[Koba Ko]

On Mon, May 11, 2020 at 9:55 PM Seth Forshee <seth.forshee at canonical.com>
wrote:

> On Mon, May 11, 2020 at 08:49:49AM -0500, Seth Forshee wrote:
> > On Mon, May 11, 2020 at 05:00:45PM +0800, koba.ko at canonical.com wrote:
> > > From: Koba Ko <koba.ko at canonical.com>
> > >
> > > BugLink: https://bugs.launchpad.net/bugs/1876844
> > >
> > > [Impact]
> > > Process of s3 resume take 7s and it's too long which is over 5s.
> > >
> > > [Fix]
> > > Reference link_active_reporting field of PCI device to determine
> whether delay is taken or not.
> > > Actual delay would be determined by taking maximum between 100ms and
> pci device's d3cold delay.
> > >
> > > [test]
> > > With the patch, the total time s3 resume is 3874.298 ms which is
> smaller than 5s.
> > >
> > > [Regression Potential]
> > > Medium. This patch only changes the rules to determine whether delay
> is taken or not.
> > > Reference the right field(link_active_reporting), but not speed of pci
> device.
> > >
> > > v2: correct BugLink typo only
> >
> > Does this problem also exist in the focal 5.4 kernel? Users of OEM
> > kernels in bionic will be moved to the focal GA kernel on upgrade to
> > 20.04, so if the problem exists there and we fix it in the osp1 kernel
> > users would see a regrssion. I would expect that any sauce patches
> > submitted for bionic OEM kernels at this point should either also be
> > submitted for focal, or else come with an explanation of why the patch
> > is not required for focal.
>
> And now I see patches for the 5.6 OEM kernel, which tells me the issue
> almost certainly does exist in the focal 5.4 kernel.
>
Hi Seth,
As per KaiHeng's comment, the patch is not low risk of regression.
Also this is a performance patch not a functional patch.
After discussion with AceLan and KaiHeng, I sent a patch only to OEM.
because we could ask our QA team to verify it first.

 Koba Ko
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