GPU hang, Intel HD Graphics 5500, UEFI

[grahamperrin]

HP EliteBook 850 G2. When booted with UEFI without CSM, the GPU hangs as shown in this photograph:

TrueOS Desktop, recent but (sorry) version unknown. Photograph taken by me 2017-03-13.

[hselasky]

Can you try using a newer drm-next kernel?

[grahamperrin]

Here's a photograph of the backtrace with a newer version of TrueOS but (sorry) I can't tell whether the drm-next is newer:

I can work around the hang by avoiding an early load of i915kms:

$ grep -i 915 /etc/rc.conf
# kldload_i915kms="i915kms"
$ 

As far as I can tell, the only penalty of that workaround is a longer period of tearing (as seen in #130 with single user mode) before the display manager and login dialogue appear.

$ about -m

===================
General information
===================

boot environment now (N) … 12.0-CURRENT-up-20170327_224112 NR 2017-03-27
       after restart (R) … 12.0-CURRENT-up-20170327_224112 NR 2017-03-27
boot loader …………………………………… BSD
            type ……………………… EFI
CPU ………………………………………………………… Intel(R) Core(TM) i7-5600U CPU @ 2.60GHz
    number of cores ……………… 4
host ……………………………………………………… momh167-gjp4-hpelitebook850g2-trueos.university.brighton.ac.uk
memory ………………………………………………… 16384 MB available, 3314 MB free
OS git branch ……………………………………………………………………………………… drm-next
OS git revision ………………………………………………………………………………… 831f60b42
OS kernel build time ………………………………………………………… Mon 2017 Mar 27 14:32:11 UTC
OS kernel identity …………………………………………… (uname -i) GENERIC
OS platform (architecture) ……………………… (uname -m) amd64
OS release level ………………………………………………… (uname -r) 12.0-CURRENT
OS version and patch level …… (freebsd-version) 12.0-CURRENT
TrueOS package set ………………… CUSTOM
TrueOS version …………………………… TrueOS-Desktop-201703201429
uptime ………………………………………………… 9:28
user  …………………………………………………… grahamperrin

More (TrueOS Desktop):

    desktop environment …… KDE
    sound card driver ………… pcm1: <Realtek (0x0280) (Analog 2.0+HP/2.0)> on hdaa1  (1p:2v/1r:4v) default
    wireless driver ……………… iwm0
    X11 drivers ………………………… intel_drv.so 

$