Arch Linux

thfischer

Member

Registered: 2017-01-03

Posts: 6

X11 displays not correctly initialized at boot, restart of DM required

Hello,
I have a strange effect on two laptops running ArchLinux but on none of the desktop systems:
When X11 starts as configured automatically during boot time, it often but not always does not recognize/initialized attached screens (both the laptops' own displays as well as external/docked displays), thus the screen stays black.

Details: On the machines I am maintaining, systemd is configured to boot up a multi-user "runlevel" where X11 and sddm as DM is started. The displays are correctly working boot time, e.g. in Grub and systemd's own boot messages. Only when X11 starts, everything goes black, external screen claim no signal and go into power save mode. It is possible to switch to a text console (e.g. Ctrl+Alt+F3), which activates internal and external screens, logins are possible and the system is working. It is possible to restart X11 through "systemctl restart sddm", after which sddm's login screen comes up and the system is working as expected.

First, I suspected some bug in sddm, but a temporary switch to lightdm brought no change.

Next I compared /var/log/Xorg.0.log both from the failed boot attempt (where everything goes black) to a log file as created when restarting the sddm service.
When filtering away differences such as time stamps and reordered messages about detected keyboards, mice, touchpads etc, the main relevant difference is that two lines (at end) are missing when comparing the following outputs.

First, the failed state:

(II) intel: Driver for Intel(R) HD Graphics
(II) intel: Driver for Intel(R) Iris(TM) Graphics
(II) intel: Driver for Intel(R) Iris(TM) Pro Graphics
(II) intel(0): Using Kernel Mode Setting driver: i915, version 1.6.0 20160711
(II) intel(0): SNA compiled from 2.99.917-746-g169c74f
(--) intel(0): Integrated Graphics Chipset: Intel(R) HD Graphics 5500
(--) intel(0): CPU: x86-64, sse2, sse3, ssse3, sse4.1, sse4.2, avx, avx2; using a maximum of 2 threads
(II) intel(0): Creating default Display subsection in Screen section
	"Default Screen Section" for depth/fbbpp 24/32
(==) intel(0): Depth 24, (--) framebuffer bpp 32
(==) intel(0): RGB weight 888
(==) intel(0): Default visual is TrueColor
(**) intel(0): Option "DRI" "3"
(II) intel(0): Output eDP1 has no monitor section
(**) intel(0): Found backlight control interface intel_backlight (type 'raw') for output eDP1
(II) intel(0): Enabled output eDP1
(II) intel(0): Output DP1 has no monitor section
(II) intel(0): Enabled output DP1
(II) intel(0): Output HDMI1 has no monitor section
(II) intel(0): Enabled output HDMI1
(II) intel(0): Output DP2 has no monitor section
(II) intel(0): Enabled output DP2
(II) intel(0): Output HDMI2 has no monitor section
(II) intel(0): Enabled output HDMI2
(II) intel(0): Output DP1-1 has no monitor section
(II) intel(0): Enabled output DP1-1
(II) intel(0): Output DP1-2 has no monitor section
(II) intel(0): Enabled output DP1-2
(II) intel(0): Output DP1-3 has no monitor section
(II) intel(0): Enabled output DP1-3
(--) intel(0): Using a maximum size of 256x256 for hardware cursors
(II) intel(0): Output VIRTUAL1 has no monitor section
(II) intel(0): Enabled output VIRTUAL1
(==) intel(0): TearFree enabled
(==) intel(0): DPI set to (96, 96)

Now the "correct" state after a restart

(II) intel: Driver for Intel(R) Integrated Graphics Chipsets:
	i810, i810-dc100, i810e, i815, i830M, 845G, 854, 852GM/855GM, 865G,
	915G, E7221 (i915), 915GM, 945G, 945GM, 945GME, Pineview GM,
	Pineview G, 965G, G35, 965Q, 946GZ, 965GM, 965GME/GLE, G33, Q35, Q33,
	GM45, 4 Series, G45/G43, Q45/Q43, G41, B43
(II) intel: Driver for Intel(R) HD Graphics
(II) intel: Driver for Intel(R) Iris(TM) Graphics
(II) intel: Driver for Intel(R) Iris(TM) Pro Graphics
(II) intel(0): Using Kernel Mode Setting driver: i915, version 1.6.0 20160711
(II) intel(0): SNA compiled from 2.99.917-746-g169c74f
(--) intel(0): Integrated Graphics Chipset: Intel(R) HD Graphics 5500
(--) intel(0): CPU: x86-64, sse2, sse3, ssse3, sse4.1, sse4.2, avx, avx2; using a maximum of 2 threads
(II) intel(0): Creating default Display subsection in Screen section
	"Default Screen Section" for depth/fbbpp 24/32
(==) intel(0): Depth 24, (--) framebuffer bpp 32
(==) intel(0): RGB weight 888
(==) intel(0): Default visual is TrueColor
(**) intel(0): Option "DRI" "3"
(II) intel(0): Output eDP1 has no monitor section
(**) intel(0): Found backlight control interface intel_backlight (type 'raw') for output eDP1
(II) intel(0): Enabled output eDP1
(II) intel(0): Output DP1 has no monitor section
(II) intel(0): Enabled output DP1
(II) intel(0): Output HDMI1 has no monitor section
(II) intel(0): Enabled output HDMI1
(II) intel(0): Output DP2 has no monitor section
(II) intel(0): Enabled output DP2
(II) intel(0): Output HDMI2 has no monitor section
(II) intel(0): Enabled output HDMI2
(II) intel(0): Output DP1-1 has no monitor section
(II) intel(0): Enabled output DP1-1
(II) intel(0): Output DP1-2 has no monitor section
(II) intel(0): Enabled output DP1-2
(II) intel(0): Output DP1-3 has no monitor section
(II) intel(0): Enabled output DP1-3
(--) intel(0): Using a maximum size of 256x256 for hardware cursors
(II) intel(0): Output VIRTUAL1 has no monitor section
(II) intel(0): Enabled output VIRTUAL1
(--) intel(0): Output eDP1 using initial mode 1920x1080 on pipe 0
(--) intel(0): Output DP1-1 using initial mode 2560x1440 on pipe 1
(==) intel(0): TearFree enabled
(==) intel(0): DPI set to (96, 96)

"eDP1" is most likely the laptop's built-in display and "DP1-1" is externaly attached display.

Comparing both outputs further, reveals another difference. The failed output reads as follows:

(II) intel(0): resizing framebuffer to 8x8

and the correct one is here:

(II) intel(0): switch to mode 1920x1080@60.0 on eDP1 using pipe 0, position (0, 0), rotation normal, reflection none
(II) intel(0): switch to mode 2560x1440@60.0 on DP1-1 using pipe 1, position (0, 0), rotation normal, reflection none
(II) intel(0): Setting screen physical size to 677 x 381

I am running an up-to-date ArchLinux on all systems. The affected systems are HP Elitebook 840 laptops, 12-18 months old. "lspci" says on the graphics controller:

00:02.0 VGA compatible controller: Intel Corporation HD Graphics 5500 (rev 09) (prog-if 00 [VGA controller])
        Subsystem: Hewlett-Packard Company ZBook 15u G2 Mobile Workstation
        Flags: bus master, fast devsel, latency 0, IRQ 51
        Memory at c0000000 (64-bit, non-prefetchable) [size=16M]
        Memory at b0000000 (64-bit, prefetchable) [size=256M]
        I/O ports at 6000 [size=64]
        [virtual] Expansion ROM at 000c0000 [disabled] [size=128K]
        Capabilities: <access denied>
        Kernel driver in use: i915
        Kernel modules: i915

The problem is that there are sooo many postings out there about people having X11 problems, that it is virtually impossible to find information specific for my problem. I am open both for direct help on my problem as well as on constructive suggestions how to improve my search practices.

Thank you on advance!