Anil F Duggirala composed on 2022-08-24 11:19 (UTC-0400):
> I am noticing that my new Dell S2421HS is detected and identified differently
> depending on when I connect it.
> If the monitor is connected when I boot up the laptop, the monitor is
> detected
> as "Dell Inc. DELL S2421HS". If the monitor is connected after logging in, it
> is detected as something like "HDMI 1 Unknown - A" (approximately).
> Does anyone have some insight into why this is happening?
> I using KDE Plasma desktiop,
# inxi -S
System:
Host: ab250 Kernel: 5.18.19-200.fc36.x86_64 arch: x86_64 bits: 64
Desktop: Trinity v: R14.0.12 Distro: Fedora release 36 (Thirty Six)
#
If I keep my second display's cable disconnected, I get this:
# grep onnec /var/log/Xorg.0.log
[ 5.313] (II) modeset(0): Output DP-1 connected
[ 5.313] (II) modeset(0): Output HDMI-1 disconnected
[ 5.313] (II) modeset(0): Output HDMI-2 disconnected
[ 5.313] (II) modeset(0): Output HDMI-3 disconnected
[ 5.313] (II) modeset(0): Output DP-2 disconnected
#
Or this:
# grep onnec /var/log/Xorg.0.log
[ 5.544] (II) modeset(0): Output DP-1 disconnected
[ 5.544] (II) modeset(0): Output HDMI-1 disconnected
[ 5.544] (II) modeset(0): Output HDMI-2 connected
[ 5.544] (II) modeset(0): Output HDMI-3 disconnected
[ 5.544] (II) modeset(0): Output DP-2 disconnected
#
It may surprise many that if I keep my second display's signal cable connected
from the PC, but with it powered off, I get this on booting instead:
# grep onnec /var/log/Xorg.0.log
[ 5.412] (II) modeset(0): Output DP-1 connected
[ 5.412] (II) modeset(0): Output HDMI-1 disconnected
[ 5.412] (II) modeset(0): Output HDMI-2 connected
[ 5.412] (II) modeset(0): Output HDMI-3 disconnected
[ 5.412] (II) modeset(0): Output DP-2 disconnected
#
Or this:
# grep onnec /var/log/Xorg.0.log
[ 5.451] (II) modeset(0): Output DP-1 connected
[ 5.451] (II) modeset(0): Output HDMI-1 disconnected
[ 5.451] (II) modeset(0): Output HDMI-2 connected
[ 5.451] (II) modeset(0): Output HDMI-3 disconnected
[ 5.451] (II) modeset(0): Output DP-2 disconnected
#
So, at "connection" time, the secondary display isn't providing any information
about it's capability, only the cable connection is "reporting" something is
connected. Some may want to rethink the definition of "connected", and not boot
with an external display attached but un-powered.
I think in most cases of non-broken firmware if the external is attached and
powered up after booting that restarting X will fix it, but with some firmware,
the only practical solution to not needing xrandr gyrations and/or keyboard work
is booting with the external connected and powered. Some DMs can be configured
to
restart X on every logout, which is what I do with KDM & TDM. Ctrl-Alt-F3
followed
by Alt-F7 can also produce the desired effect when a DM that doesn't put X on
tty1
is in use.
KDE is reportedly in process of trying to come up with a system of keeping each
display suitably identified so that connecting or disconnecting it doesn't make
a
mess of desktop organization. There are many bug reports in this area, and a lot
of work lately identifying and marking duplicates.
Association of "A" with an HDMI port has its roots in the kernel:
# ls -1 /sys/class/drm
card1
card1-DP-1
card1-DP-2
card1-HDMI-A-1
card1-HDMI-A-2
card1-HDMI-A-3
renderD128
version
It can be exposed thus:
# inxi -Gaz
Graphics:
Device-1: Intel HD Graphics 630 vendor: ASUSTeK driver: i915 v: kernel
arch: Gen-9.5 process: Intel 14nm built: 2016-20 ports:
active: DP-1,HDMI-A-2 empty: DP-2,HDMI-A-1,HDMI-A-3 bus-ID: 00:02.0
chip-ID: 8086:5912 class-ID: 0300
Display: x11 server: X.Org v: 1.20.14 driver: X: loaded: modesetting
alternate: fbdev,vesa gpu: i915 display-ID: :0 screens: 1
Screen-1: 0 s-res: 3600x1200 s-dpi: 120 s-size: 762x254mm (30.00x10.00")
s-diag: 803mm (31.62")
Monitor-1: DP-1 pos: primary,left model: Dell P2213 serial: <filter>
built: 2013 res: 1680x1050 hz: 60 dpi: 90 gamma: 1.2
size: 473x296mm (18.62x11.65") diag: 558mm (22") ratio: 16:10 modes:
max: 1680x1050 min: 720x400
Monitor-2: HDMI-A-2 mapped: HDMI-2 pos: right model: NEC EA243WM
serial: <filter> built: 2011 res: 1920x1200 hz: 60 dpi: 94 gamma: 1.2
size: 519x324mm (20.43x12.76") diag: 612mm (24.1") ratio: 16:10 modes:
max: 1920x1200 min: 640x480
OpenGL: renderer: Mesa Intel HD Graphics 630 (KBL GT2) v: 4.6 Mesa 22.1.4
direct render: Yes
#
--
Evolution as taught in public schools is, like religion,
based on faith, not based on science.
Team OS/2 ** Reg. Linux User #211409 ** a11y rocks!
Felix Miata
_______________________________________________
users mailing list -- users@lists.fedoraproject.org
To unsubscribe send an email to users-le...@lists.fedoraproject.org
Fedora Code of Conduct:
https://docs.fedoraproject.org/en-US/project/code-of-conduct/
List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines
List Archives:
https://lists.fedoraproject.org/archives/list/users@lists.fedoraproject.org
Do not reply to spam, report it:
https://pagure.io/fedora-infrastructure/new_issue
