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

[Bengt Ahlgren]

John Baldwin <jhb at freebsd.org> writes:

> On Wednesday, September 04, 2013 3:14:32 pm Bengt Ahlgren wrote:
>> Jung-uk Kim <jkim at FreeBSD.org> writes:
>> 
>> > On 2013-09-04 09:29:35 -0400, John Baldwin wrote:
>> >> On Tuesday, September 03, 2013 6:58:55 pm Jung-uk Kim wrote:
>> >>> On 2013-09-03 16:47:47 -0400, John Baldwin wrote:
>> >>>> Even with that hacked so I force vgapm0 and dpms0 to attach, I 
>> >>>> still can't resume in console mode, ...
>> >>> 
>> >>> What happens?  Does it panic, hang, or just no backlight?
>> >> 
>> >> Just no backlight.  It resumes fine and if I do it in multiuser I 
>> >> can ssh in, etc.  It's just the backlight that doesn't resume.  I
>> >> was hopeful dpms.ko would fix that, but it didn't. :(
>> >
>> > Ah, that's a well-known problem and we cannot fix it without help of
>> > machine-specific code, e.g., drm1/drm2.  Actually, both acpi_video and
>> > dpms try to restore video settings but nothing worked for Intel GPUs +
>> > LVDS + LCD panel AFAIK.
>> >
>> >> I think i915drm has code to specifically turn on the backlight as
>> >> I get some weird error message in the kernel console about a
>> >> timeout trying to turn the panel off during suspend when I'm in X.
>> > So, I guess it has an ordering issue.  If my memory serves, drm1 was
>> > okay with vesa, however.  I *think* it accidentally worked because of
>> > automatic VT-switching, which is still broken for KMS.
>> 
>> Yes, perhaps, but there is also the sysctl hw.acpi.reset_video which I
>> have enabled on my older hardware (TP X40 running 8.3-REL and an old
>> Xorg server) for it to work properly.  (I however have some faint memory
>> that reset_video might a no-op these days, or?)  In this old mail
>> regarding reset_video, there is a thought that it could be good with
>> "more" reinitialisation:
>> 
>> http://lists.freebsd.org/pipermail/freebsd-acpi/2006-July/002959.html
>> 
>> I however have one datapoint that I think contradicts John's thought.
>> This is on a X201 with stable/9 and no options VESA.  I first just
>> booted up and stayed in text console, suspended and resumed.  No
>> backlight, of course, and also no content on the LCD, it is completely
>> black.  Then, I started Xorg with KMS.  Still no backlight, but you can
>> see that the LCD is driven with the desired content, which is one step
>> forward.  Finally, I suspended and resumed, but no difference, the
>> backlight is still off.  Xorg/KMS didn't manage to turn the backlight
>> on, so the text console suspend/resume cycle managed to persistently
>> turn the backlight off.
>
> Try starting X before you suspend the first time.  For me resume works
> fine if I do that.

Yes, it does work then for me too - knew that already.

Bengt