Re: ThinkPad - suspend-to-RAM intel-x86 issues and tests

[David Brownlee <abs%absd.org@localhost>]

On Tue, 27 Nov 2018 at 18:10, David Brownlee <abs%absd.org@localhost> wrote:
>
> On Tue, 27 Nov 2018 at 08:27, Masanobu SAITOH <msaitoh%execsw.org@localhost> wrote:
> >
> >   Hi, David.
> >
> > On 2018/11/26 6:11, David Brownlee wrote:
> > > I've bisected the changes against the github src copy, and it looks like the suspend/resume issue is related to the following commit:
> > >
> > > commit 0fe469276f49bf0dc003300e0b8a35a80b7b246d (HEAD)
> > > Author: jdolecek <jdolecek%NetBSD.org@localhost>
> > > Date:   Mon Oct 22 20:57:07 2018 +0000
> > >
> > >      enable MSI support where available, blatantly copied from jmcneill's msk(4)
> > >
> > > I tried building from HEAD with just that one commit reverted, and my T420s suspends and resumes again!
> > >
> > > iwn0 is still non responsive after resume and wm0 will not pick up an IP via dhcpcd, but the disk responds :-p
> >
> >   (Note that I'm not familiar with suspend/resume though...)
> >
> >   Our pci_suspend()/pci_resume() copy only first 16 bytes of each PCI
> > config space. Other OSes copy some other control registers and
> > MSI/MSI-X capability area.
> >
> >   Could you dump all PCI config space both before and after suspend with:
> >
> >         http://www.netbsd.org/~msaitoh/pcidump
> >
> > and put the two output somewhere? Diffing the two output will teach
> > us what we have to do.
> >
> >   Thanks in advance.
>
> Let me just install to a USB stick to give me a working filesystem
> from which to run pcidump after resume :-p

Collecting a pre-suspend dump was easy, but getting post-resume turned
out to be a little more involved :)
- root on wd0 on ahcisata - times out on resume
- root on sd0 on usb on xhci - times out on resume
- root on sd0 on usb on uhci - loses the root filesystem mount point on resume
- install image - doesn't have the libs to run pcictl
- install image, then chroot to mfs with extracted base - suspends but
video does not come back (no drm)
- root on wd0, then chroot to mfs with extracted base, suspend &
resume, then mount sd0 on usb on uhci to save data - \o/

After all that it occurred to me I could have probably run the
suspend/resume with an older NetBSD version where MSI was not being
used. Still, interesting puzzle to try, and useful technique to stash.

Files for the ThinkPad T420s:

http://ftp.netbsd.org/pub/NetBSD/misc/abs/acpi-suspend-resume/pcidump.pre
http://ftp.netbsd.org/pub/NetBSD/misc/abs/acpi-suspend-resume/pcidump.post

Thanks for looking at this!

David