suspend/resume on Lenovo X1 (regression from reports on wiki)

[Laura Marie Feeney]

On 08/29/13 18:44, Adrian Chadd wrote:
> Hi!

>
> Let's not finish this just yet! I'd like to try and nail down exactly
> what's going on so PRs can be filed.

Absolutely. (I was thinking to do this off-list to minimize spam.)

> * Is this with 9.2-RC2?
Yes this is 9.2-RC2.  I think the problem is that the simple install 
path ends up with out-of-date components, rather than anything wrong 
with the components that should be used.

Are you wiling to try out a -HEAD snapshot to
> make sure this stuff in -10 is also going to work?
Yes, but probably not until the weekend.

> * Ok, so if you have no VESA option, does suspend/resume work in console
> mode?
No.  The system resumes (can ssh in), but the backlight doesn't come on 
(using a flashlight, I don't see any video mode running either).  See 
http://www.sics.se/~lmfeeney/9.2-RC2/messages_console.

> * Try manually setting the cpu frequency low and high (sysctl dev.0.cpu
> - you can change 'freq') - see if that fixes your speed issues. Someone
> else has reported this.

Before and after resume, dev.cpu.0.freq: 1700.  Setting to 100 and back 
to 1700 didn't seem to have much effect.

Basically, what I see is that after resume, it seems to be easier to 
increase the load on the cpu (i.e. looking at top) by e.g. scrolling 
quickly.

My "test" sequence was: boot,
'startx' (so twm and a couple xterms)
'top (in one xterm)
'xterm -sb -geometry 100x65' (make xterm w/ scrollbar),
'cat /var/log/messages' (in the new xterm)
scroll very rapidly up and down for ~20sec
look at top output

suspend/resume and repeat the scrolling. The load seems to go quite a 
bit higher after resuming (CPU from ~10% to ~20%).  But this is 
definitely not a scientific test AND I was primed by Gleb Smirnoff's 
comments to look for a performance hit.

For sensible use (i.e. not madly scrolling), I don't sense slowdown. 
But the machine is completely minimal: portmaster and xorg are the only 
ports installed.  It could be that KDE + web + mail + applications 
managing lots of things on the screen would show a big slowdown, as 
reported by others.

It would probably make sense to define some  metric that people who have 
reported problems can compare before and after suspsend/resume.

Best,
Laura