Re: kern/53795: i915drmkms causes crash on boot with Atom N270/945GSE netbook

["David H. Gutteridge" <david%gutteridge.ca@localhost>]

The following reply was made to PR kern/53795; it has been noted by GNATS.

From: "David H. Gutteridge" <david%gutteridge.ca@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: kern/53795: i915drmkms causes crash on boot with Atom
 N270/945GSE netbook
Date: Mon, 07 Jan 2019 21:16:06 -0500

 Further questions and comments:
 
 You didn't mention what make and model this machine is? I infer from
 looking at the dmesg output that it's a 3rd generation Classmate by
 Intel? On that basis, I tried to see if there were any quirks listed
 for it in a recent version of the Linux i915 driver, but didn't note
 anything.
 
 Which specific Linux kernel versions does it work on? Same with
 OpenBSD? NetBSD's i915 code is based on Linux 4.4, as is OpenBSD's
 (for the most part). I tried comparing what had changed between 4.4
 and 4.20 in Linux, but there's too much churn to be useful without
 having more to go on to narrow it down. (And, indeed, it could be
 the problem is somewhere in BSD-specific code, for all I know.)
 
 Is there any more dmesg output than that? I'd expect if you ended up
 with working ssh access there'd be more of it. The initial ACPI output
 looks weird, i.e. I doubt all those video outputs exist on the machine.
 I have no idea if that's anything more than a red herring, though.
 
 You could enable debugging via the appropriate sysctl setting for more
 verbose output (assuming it gets that far, per previous question). To
 do so, you can set hw.drm2.drm_debug to a suitable value (e.g. 0xf) in
 /etc/sysctl.conf. That might tell us something more.
 
 Something else you could try -- if you're really curious -- would be to
 enable the old i915drm driver instead, and see what happens there. (I
 used to use the old driver on my LG X110.)
 
 Dave