Thinkpad T410: resume broken

[John Baldwin]

On Thursday, February 18, 2016 09:47:12 PM Alexey Dokuchaev wrote:
> On Thu, Feb 18, 2016 at 06:50:34AM -0800, John Baldwin wrote:
> > On Thursday, February 18, 2016 08:13:38 PM Alexey Dokuchaev wrote:
> > vesa.ko shouldn't be working with KMS.  KMS turns off the legacy VGA
> > emulation in the hardware when it starts which prevents VESA from working
> > (VESA requires the legacy VGA interface).
> 
> Hmm, could this explain why vesa.ko can be loaded from loader.conf, but
> not via kldload(8)?  OTOH, kldload'ing it later does not seem to work
> (ir)regardless of whether i915kms.ko is loaded or not...

You might load it from loader.conf but it might then fail with an error about
failing to register in dmesg.  In that case it is effectively ignored.

> > I never have to hit the power button more than once to resume on a laptop
> > where resume works though.
> > 
> > (True on my X220 and on a T440 both with Intel or Radeon graphics (all
> > using KMS).
> 
> I'm about to try fresh -CURRENT on some HP AMD APU-based laptops, hence
> I'll ask: do aforementioned laptops suspend/resume without issues in X11
> or on the naked console as well?  (In a shop, I could only quickly test
> our X11-less memstick image.)

Once KMS is loaded they resume fine.  They require the KMS driver to turn
the LCD panel back on.  Without KMS they also "resume" but the screen is off
so you can't see anything.  However, you can type blind and run commands.
If the network is up you can ssh into the laptop, etc. after resume.

> > > Needless to say, suspend/resume worked nearly flawlessly under stable/8
> > > and stable/7 FWIW.
> > 
> > If it worked here, then this means you could try using sc(4) + the old drm
> > (not drm2).  This means your laptop is old enough to still turn the LCD panel
> > back on in its BIOS during resume like my HP netbook.  However, I don't know
> > for how much longer Xorg will support the older drm (if it even does now).
> 
> Well, technically, my laptop *does* resume with vt(4) + i915kms, just it
> takes a lot of power button hits and quite some time (up to several minutes),
> unless it dies somewhere during the process.  I'll retest it against
> GENERIC and report in a separate email.  On a related note, how does one
> configure sc(4) with old drm (vs. drm2) shall I need to try that?

On HEAD you need to set kern.vty=sc to use sc(4) instead of vt(4).  For
suspend/resume without X that should be sufficient.  You would only need
the old drm drivers for X.

> > FWIW, the HP netbook resumes fine with KMS as well for me.  One caveat
> > though is that if you are using vt(4) and haven't yet loaded KMS it won't
> > resume (due to vt(4) not having the equivalent of VESA).  With sc(4) the
> > netbook was always able to resume.
> 
> Right.  So far, I've been booting, kldloading i915kms.ko, zzz(8), resume.
> No X.Org was involved -- given how fragile suspend/resume is ATM, I'd like
> to iron out the issues with the pure console first.

Note that for the HP netbook, resume in console with vt(4) does not work
without KMS (due to vt(4) not supporting VESA).

-- 
John Baldwin