[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]
Re: kern/49398 (i386-current GENERIC (i915drmkms) boot hangs if monitor powered off)
The following reply was made to PR kern/49398; it has been noted by GNATS.
From: "John D. Baker" <jdbaker%mylinuxisp.com@localhost>
Subject: Re: kern/49398 (i386-current GENERIC (i915drmkms) boot hangs if
monitor powered off)
Date: Tue, 9 Jun 2015 20:20:52 -0500 (CDT)
On Thu, 14 May 2015, John D. Baker wrote:
> On Thu, 14 May 2015, riastradh%NetBSD.org@localhost wrote:
> > State-Changed-Why:
> > Via the serial console, can you get a stack trace from ddb?
> When last I tried, I could not. The machine was completely hung and
> required power-cycle to regain control.
I've finally gotten things updated to the latest HEAD. There has been
no change in behavior since the last update of this PR. As I noted
above, the machine is completely wedged at this point, so dropping to
DDB is not possible. Power-cycle is the only way out.
> > If not, we can try printf debugging. I'd start by adding printfs
> > around all the calls to drm_add_edid_modes in i915, and throughout
> > drmfb_attach. That should be enough to get started, but I can supply
> > a patch if you'd like.
If you could supply said patch, I think that would be the simplest way
The only other complication I see is that when the console is on the
serial port, the VGA output is disabled when inteldrm attaches, so
there's no video output anyway. I read a note about "genfb" stealing
registers, but I'm using a custom kernel which omits "genfb" entirely
and the video output is still disabled.
> > Also: does this happen on any machine other than your i845?
> I may have access to other intel-graphics-equipped machines I can poke
> at, but it will be early June before I can try.
I have access to at least one, possibly two, other machines with intel
graphics that I can test. I'm in the process of setting those up now.
One other possibility has occurred to me. Perhaps the monitor I've
been using is flaky (IIUC, EDID data should be readable even if the
monitor is off). Unfortunately, testing the machine in question with
another monitor and the monitor with another machine is a rather
|/"\ John D. Baker, KN5UKS NetBSD Darwin/MacOS X
|\ / jdbaker[snail]mylinuxisp[flyspeck]com OpenBSD FreeBSD
| X No HTML/proprietary data in email. BSD just sits there and works!
|/ \ GPGkeyID: D703 4A7E 479F 63F8 D3F4 BD99 9572 8F23 E4AD 1645
Main Index |
Thread Index |