Monitor id detection via HDMI is variable

[Anil F Duggirala]

hello,
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,

thank you,

Anil

[Barry]

>  On 24 Aug 2022, at 16:19, Anil F Duggirala
> <anilduggirala(a)fastmail.fm&gt; wrote:
>  
>  hello,
>  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, 
Check dmesg for any messages about the video interface or monitor.
Are there any messages about edid?

Barry

>  
>  thank you,
>  
>  Anil
>  
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[Anil F Duggirala]

On Wednesday, August 24, 2022 11:46:24 AM -05 Barry wrote:
>  Check dmesg for any messages about the video interface or monitor.
>  Are there any messages about edid? 
Hello Barry,
I tried looking in dmesg but cannot find anything mentioning edid. I'm not sure 
this would help me. Detection appears to be working fine when I boot with the 
monitor connected. It does not do the nice detection when I connect the 
monitor after logging in. Dmesg would not show me anything that happens after 
login right?

I will try checking again, when I have the monitor available again to see if 
maybe I can find something related to the monitor in dmesg.

thank you,

[Tim]

On Wed, 2022-08-24 at 21:14 -0500, Anil F Duggirala wrote:
>  Dmesg would not show me anything that happens after 
>  login right? 
No.

On all the systems I use, it'll show things as they happen.  Plug in a
USB flash drive, and see what it discovers.  Unplug it, see what
happens next.  Et cetera.

I also look at /var/log/messages, other people use journalctl, but I
find the messages file easier to deal with.
 
-- 
 
uname -rsvp
Linux 3.10.0-1160.76.1.el7.x86_64 #1 SMP Wed Aug 10 16:21:17 UTC 2022 x86_64
 
Boilerplate:  All unexpected mail to my mailbox is automatically deleted.
I will only get to see the messages that are posted to the mailing list.

[Samuel Sieb]

On 2022-08-24 22:09, Tim via users wrote:
>  On Wed, 2022-08-24 at 21:14 -0500, Anil F Duggirala wrote:
> > Dmesg would not show me anything that happens after
> > login right?
>  
>  No.
>  
>  On all the systems I use, it'll show things as they happen.  Plug in a
>  USB flash drive, and see what it discovers.  Unplug it, see what
>  happens next.  Et cetera.
>  
>  I also look at /var/log/messages, other people use journalctl, but I
>  find the messages file easier to deal with. 
You must have upgraded from a much older version or else you've made 
some changes.  By default there is no /var/log/messages file.  The 
journal is the default system and it is much easier to use.

[Tim]

Tim:
> > I also look at /var/log/messages, other people use journalctl,
> but I
> > find the messages file easier to deal with. 
Samuel Sieb:
>  You must have upgraded from a much older version or else you've
> made 
>  some changes. 
Not an upgrade, a fresh install.  And I don't recall making any changes
related to the messages file creation.  My post install logs just show
things installing vlc, gstreamer and lame codecs, chromium and google-
chrome browsers, evolution, gimp, gvim, musescore, autofs.

On the other PC:
uname -rsvp
Linux 5.18.16-200.fc36.x86_64 #1 SMP PREEMPT_DYNAMIC Wed Aug 3 15:44:49 UTC 2022 x86_64

It's the Mate spin, if that makes any difference.

>  By default there is no /var/log/messages file.  The 
>  journal is the default system and it is much easier to use. 
This is some new definition of easier that I'm unfamiliar with.

I have to learn commands I don't know, as opposed to tail, less, and
grep, that's on virtually all Linuxes.  The same commands I use on
every other log file I read (Apache logs, mail logs, etc).  I have to
keep referring to the man file to be able to use journalctl.  And it's
a right pig to deal with it loading a huge amount of data as opposed to
reading the last messages file since it was rolled over.

Yep, definitely not the "easier" in my dictionary.

-- 
 
uname -rsvp
Linux 3.10.0-1160.76.1.el7.x86_64 #1 SMP Wed Aug 10 16:21:17 UTC 2022 x86_64
 
Boilerplate:  All unexpected mail to my mailbox is automatically deleted.
I will only get to see the messages that are posted to the mailing list.

[Barry Scott]

>  On 25 Aug 2022, at 09:31, Tim via users
> <users(a)lists.fedoraproject.org&gt; wrote:
>  
>  Tim:
> >> I also look at /var/log/messages, other people use journalctl, but I
> >> find the messages file easier to deal with.
>  
>  Samuel Sieb:
> > You must have upgraded from a much older version or else you've made 
> > some changes.
>  
>  Not an upgrade, a fresh install.  And I don't recall making any changes
>  related to the messages file creation.  My post install logs just show
>  things installing vlc, gstreamer and lame codecs, chromium and google-
>  chrome browsers, evolution, gimp, gvim, musescore, autofs. 
I just check my KDE VM that is a fresh install and it has rsyslog installed and the old
school
/var/log/messages etc.

I'll have to run around all my systems and dnf remove rsyslog to clean mess of logs
up!

>  
>  On the other PC:
>  uname -rsvp
>  Linux 5.18.16-200.fc36.x86_64 #1 SMP PREEMPT_DYNAMIC Wed Aug 3 15:44:49 UTC 2022 x86_64
>  
>  It's the Mate spin, if that makes any difference.
>  
> > By default there is no /var/log/messages file.  The 
> > journal is the default system and it is much easier to use.
>  
>  This is some new definition of easier that I'm unfamiliar with.
>  
>  I have to learn commands I don't know, as opposed to tail, less, and
>  grep, that's on virtually all Linuxes.  The same commands I use on
>  every other log file I read (Apache logs, mail logs, etc).  I have to
>  keep referring to the man file to be able to use journalctl.  And it's
>  a right pig to deal with it loading a huge amount of data as opposed to
>  reading the last messages file since it was rolled over. 
You need to know a small number of new commands and its worth it.
Because the journal is structured log records you can query it in useful and fast ways.

Want to know what sshd did since boot?

[root@armf36 ~]# journalctl --boot 0 --unit sshd 
Aug 25 15:28:58 armf36.chelsea.private systemd[1]: Starting sshd.service - OpenSSH server
daemon... 
Aug 25 15:28:58 armf36.chelsea.private sshd[1012]: Server listening on 0.0.0.0 port 22. 
Aug 25 15:28:58 armf36.chelsea.private sshd[1012]: Server listening on :: port 22. 
Aug 25 15:28:58 armf36.chelsea.private systemd[1]: Started sshd.service - OpenSSH server
daemon.

Don't like typing --boot well its this:

journalctl -b 0 -u sshd

Want to know what happened in that last few minutes?

[root@armf36 ~]# journalctl --since=15:31 
Aug 25 15:31:24 armf36.chelsea.private systemd[1]: fprintd.service: Deactivated
successfully. 
Aug 25 15:31:24 armf36.chelsea.private audit[1]: SERVICE_STOP pid=1 uid=0 auid=4294967295
ses=4294967295 s> 
Aug 25 15:31:24 armf36.chelsea.private audit: BPF prog-id=0 op=UNLOAD 
Aug 25 15:31:28 armf36.chelsea.private systemd[1]: systemd-hostnamed.service: Deactivated
successfully.

Its got grep built in as well. so you can combine grep with any of the above.

[root@armf36 ~]# journalctl --since=15:31 --grep STOP 
Aug 25 15:31:24 armf36.chelsea.private audit[1]: SERVICE_STOP pid=1 uid=0 auid=4294967295
ses=4294967295 s> 
Aug 25 15:31:28 armf36.chelsea.private audit[1]: SERVICE_STOP pid=1 uid=0 auid=4294967295
ses=4294967295 s>

>  
>  Yep, definitely not the "easier" in my dictionary. 
I have to support systems without journald and its slower to get to the info need.

Barry

>  
>  -- 
>  
>  uname -rsvp
>  Linux 3.10.0-1160.76.1.el7.x86_64 #1 SMP Wed Aug 10 16:21:17 UTC 2022 x86_64
>  
>  Boilerplate:  All unexpected mail to my mailbox is automatically deleted.
>  I will only get to see the messages that are posted to the mailing list.
>  
>  _______________________________________________
>  users mailing list -- users(a)lists.fedoraproject.org
>  To unsubscribe send an email to users-leave(a)lists.fedoraproject.org
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[George N. White III]

On Thu, Aug 25, 2022 at 11:37 AM Barry Scott <barry(a)barrys-emacs.org&gt; wrote:

>  I have to support systems without journald and its slower to get to the
>  info need.
>  
I encounter younger users who will only consider GUI tools.  With
traditional log files
they can use a file browser to find a log file, then try to open the
desired log in some
editor, but get access errors.  Many are working on VM's in their
institution's server
farm and may not be given root privileges, but journalctl read access for
non-root users
can be enabled by adding them to the systemd-journal group.

For GUI-only users  https://github.com/pentix/qjournalctl looks helpful,
but it is a QT5
app.  Emacs has a work-in-progess journalctl-mode <
https://github.com/SebastianMeisel/journalctl-mode>;,
but emacs is not popular with the younger set who were trained on MS Word
in school,

-- 
George N. White III

[Roger Heflin]

the command dmesg will tell you all kernel messages from the start of
the buffer to now.

You probably want to find the Wayland/Xorg log file and see what it
says about edid.

/var/log/Xorg* for Xorg, I don't use wayland but its log files should
be a the same location.

And how it works or does not work may depend on the firmware/driver
for your video card, and or the type of video card.

On Wed, Aug 24, 2022 at 9:15 PM Anil F Duggirala
<anilduggirala(a)fastmail.fm&gt; wrote:
>
> On Wednesday, August 24, 2022 11:46:24 AM -05 Barry wrote:
> > Check dmesg for any messages about the video interface or monitor.
> > Are there any messages about edid?
>
> Hello Barry,
> I tried looking in dmesg but cannot find anything mentioning edid. I'm not sure
> this would help me. Detection appears to be working fine when I boot with the
> monitor connected. It does not do the nice detection when I connect the
> monitor after logging in. Dmesg would not show me anything that happens after
> login right?
>
> I will try checking again, when I have the monitor available again to see if
> maybe I can find something related to the monitor in dmesg.
>
> thank you,
>
> _______________________________________________
> users mailing list -- users(a)lists.fedoraproject.org
> To unsubscribe send an email to users-leave(a)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
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[Felix Miata]

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