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#1 2018-11-19 02:53:20

ddwmusic
Member
Registered: 2017-07-23
Posts: 21

External monitors sometimes not detected

Quite often, XFCE fails to detect when an HDMI monitor or projector is plugged in. ThinkPad E470c, Ubuntu Studio 16.04, XFCE 4.12.

My "Display" settings panel enables "Configure new displays when connected."

It seems that it pretty much always works if the cable is plugged into the monitor first, and it's a direct cable to the computer. In that case, the Display control panel opens automatically, along with a second panel to choose mirror displays, left or right etc.

But, last weekend, in a live-coding situation (where my screen is supposed to be projected), the video guy said it was a direct line from the projector, but I got nothing. Cable plugged in on the other end, and I stuck it into my machine, and literally nothing happened -- no signal to the projector, no panels popping up on my machine, and when I manually opened Display, only one monitor (the laptop's built-in screen) was available.

I've seen, in a classroom at my school, that I can use the projector if I plug it directly, but if I go through an automated A-B switch, XFCE fails to detect.

So it kind of looks to me like XFCE might be detecting that something is plugged in, but isn't able to contact the external display quickly -- and then it gives up (where other display managers might wait a little longer, or try multiple times).

I'm hoping in the next year to do more performing, with screen projection. It's important to me that I can go into an unfamiliar place and have some confidence of connecting an external display. As of now, short of bringing my own projector, I don't have that confidence. The projector in last Saturday's venue totally failed me. They happened to have a TV on the wall, and that worked, but... why does it come down to backup equipment, rather than the computer working properly?

Why does the Display control panel not have a button to scan manually for external displays, if the first attempt failed?

I'd be happy with a commandline workaround.

Any ideas?
James

Last edited by ddwmusic (2018-11-19 02:54:01)

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#2 2018-11-23 05:32:51

ddwmusic
Member
Registered: 2017-07-23
Posts: 21

Re: External monitors sometimes not detected

Hm... Well, lack of information is information itself.

As of now, the answer seems to be, install a different desktop environment. That's a pity as there's rather a lot that I like in XFCE, but if external monitor detection is unreliable, I can't use it.

OK.

James

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#3 2018-11-23 13:13:11

ToZ
Moderator
From: Canada
Registered: 2011-06-02
Posts: 4,860

Re: External monitors sometimes not detected

ddwmusic wrote:

Ubuntu Studio 16.04, XFCE 4.12.

What version of xfce4-settings is packaged with this distro:

xfsettingsd -V

I've seen, in a classroom at my school, that I can use the projector if I plug it directly, but if I go through an automated A-B switch, XFCE fails to detect.

Is it being detected by kernel/udev/xorg? Try running:

xrandr

...before and after you connect. Does xrandr see the new device?

Last edited by ToZ (2018-11-23 13:19:13)

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#4 2018-11-23 22:01:02

mint4all
Member
From: America
Registered: 2018-08-21
Posts: 71

Re: External monitors sometimes not detected

ddwmusic wrote:

Quite often, XFCE fails to detect when an HDMI monitor or projector is plugged in. ThinkPad E470c, Ubuntu Studio 16.04, XFCE 4.12. ...

Greetings!

Over the years, i've used a few of external monitors & projectors, using assorted laptops with Win-xp, Win-7 & Ubuntu-based DEs (12.x, 14.x, 16.x). More often than not, it was a hit/miss scenario. For a presenter, or speaker, an absolute nightmare. Worse, the "helpful' techies/geeks often were of little help to get my setup working, and on occasion made it worse ...

Eventually, i got stable results by (a) using my own top-quality cables, (b) bypassing ANY & ALL A-B switches, (c) powerup the external monitor & toggle the proper input source, only then (d) powerup my laptop(s). Starting from a COLD boot generally forced the OS/kernel to properly detect the setup/connection. Only then did i use the Fn-keys to toggle the external-video port; lastly, i used the control panel/display manager to configure the external display.

To sum it up, this is m/l an Ubuntu-related issue, and less of an xfce-deficiency. Ubuntu Studio 16.04 is an LTS, but it will reach eol next spring, so you may need to try 18.04 and its newer kernels (latest news: 18.04 may get 10 years of support). Hopefully, these kernels' hdmi-support has improved since the 4.4.x kernel series ...

Upshot: fwiw ... no saved sessions, no suspense or hibernate, always start with a cold boot.

Cheers, m4a


Linux Mint 18.3-xfce & Linux Mint 19-xfce  -- Dell Precision T1500 Desktops -- Toshiba Satellite Laptop -- Family & Community Support re. Linux

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#5 2018-11-24 08:26:56

ddwmusic
Member
Registered: 2017-07-23
Posts: 21

Re: External monitors sometimes not detected

ToZ wrote:
ddwmusic wrote:

Ubuntu Studio 16.04, XFCE 4.12.

What version of xfce4-settings is packaged with this distro:

xfsettingsd -V

Thanks for the reply -- it's: xfsettingsd 4.12.0

Is it being detected by kernel/udev/xorg? Try running:

xrandr

...before and after you connect. Does xrandr see the new device?

Will try that next time I'm there (Tuesday).

James

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#6 2018-11-24 08:29:46

ddwmusic
Member
Registered: 2017-07-23
Posts: 21

Re: External monitors sometimes not detected

mint4all wrote:

To sum it up, this is m/l an Ubuntu-related issue, and less of an xfce-deficiency. Ubuntu Studio 16.04 is an LTS, but it will reach eol next spring, so you may need to try 18.04 and its newer kernels (latest news: 18.04 may get 10 years of support). Hopefully, these kernels' hdmi-support has improved since the 4.4.x kernel series ...

Upshot: fwiw ... no saved sessions, no suspense or hibernate, always start with a cold boot.

Thanks for the tips.

I'd thought it might be XFCE related because, on at least one occasion on my old laptop (where I had installed both XFCE and Gnome 3), Gnome 3 did detect the display while XFCE did not. I need to do more testing on this machine.

Disheartening that it's so difficult for hardware and OS makers to get right...

James

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#7 2018-12-02 01:51:29

ddwmusic
Member
Registered: 2017-07-23
Posts: 21

Re: External monitors sometimes not detected

ToZ wrote:

Is it being detected by kernel/udev/xorg? Try running:

xrandr

...before and after you connect. Does xrandr see the new device?

Finally had a chance to try. Bad news. To get this, I unplugged the media lab's projector from the Mac workstation at the podium and plugged it directly into my machine. There used to be a switch box but I found it had been disconnected long ago.

HDMI-1 disconnected (normal left inverted right x axis y axis)
DP-1 disconnected (normal left inverted right x axis y axis)
HDMI-2 disconnected (normal left inverted right x axis y axis)

Well, I'm stuck for now. I have a performance December 16. Experience tells me that a major OS version upgrade will take at least a week to stabilize, and I can't afford any downtime. I don't dare upgrade until the semester break.

It does seem to work better with monitors and TVs, so for the performance, we might have to do something stupid like hook up an external monitor and train a video camera on it.

Anyway, thanks for the tips... it seems like the tl;dr answers are 1. Hope they improved it in 18.04 and 2. Maybe try a different distro.

James

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#8 2018-12-02 17:03:42

mint4all
Member
From: America
Registered: 2018-08-21
Posts: 71

Re: External monitors sometimes not detected

I agree with you -- this is very discouraging sad

Judging by Lenovo's specs, @ https://psref.lenovo.com/syspool/Sys/PD … _specs.pdf , your laptop is certainly up for the job. However, it did ship with windoz, right? Is this a dual-boot system, with UbS (ubuntu studio) installed later, or is this a fresh install after a thorough disk-wipe?

As you can see on distrowatch, @ https://distrowatch.com/table.php?distr … untustudio , the latest version of UbS is 18.10 ... It comes with a whole load of upgrades, a better kernel, upgraded xfce4, etc. I'd try THAT version with a live disc/usb and see how it goes.

Just in case, have you swapped hdmi-cables?

Lastly, give us some info how your system is configured. Please run "inxi -Fxz" in a terminal and post the results -- there could be a video-driver issue (UbS-default vs. nvidia) that might just be the real problem.

Cheers, m4a


Linux Mint 18.3-xfce & Linux Mint 19-xfce  -- Dell Precision T1500 Desktops -- Toshiba Satellite Laptop -- Family & Community Support re. Linux

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#9 2018-12-03 00:57:55

ddwmusic
Member
Registered: 2017-07-23
Posts: 21

Re: External monitors sometimes not detected

mint4all wrote:

I agree with you -- this is very discouraging sad

Judging by Lenovo's specs, @ https://psref.lenovo.com/syspool/Sys/PD … _specs.pdf , your laptop is certainly up for the job. However, it did ship with windoz, right? Is this a dual-boot system, with UbS (ubuntu studio) installed later, or is this a fresh install after a thorough disk-wipe?

It is dual-boot -- unfortunately, I lost my Microsoft password so I haven't booted into Windows in over a year.

(And no, I can't recover the password because I registered the system using a temporary mobile number -- that was necessary because I needed to set up the system immediately, but I couldn't get my real number back right away because it, along with all of my IDs, were lost in a boat fire on holiday -- so now I don't have the password, and I don't have the phone number associated with the Microsoft account, and Microsoft can do nothing about that. TL;DR No, I won't be booting into Windows to do any tests. I did, about a year ago, test the media lab projector with Windows -- no problem -- so it definitely isn't a hardware issue.)

As you can see on distrowatch, @ https://distrowatch.com/table.php?distr … untustudio , the latest version of UbS is 18.10 ... It comes with a whole load of upgrades, a better kernel, upgraded xfce4, etc. I'd try THAT version with a live disc/usb and see how it goes.

Live USB... OK, not a bad idea.

Just in case, have you swapped hdmi-cables?

I don't have any control over the cables in the environments where I've had problems.

Lastly, give us some info how your system is configured. Please run "inxi -Fxz" in a terminal and post the results -- there could be a video-driver issue (UbS-default vs. nvidia) that might just be the real problem.

OK, relevant bits:

$ inxi -Fxz
System:    Host: xiaogou Kernel: 4.15.0-39-lowlatency x86_64 (64 bit gcc: 5.4.0)
           Desktop: Xfce 4.12.3 (Gtk 2.24.28) Distro: Ubuntu 16.04 xenial
Machine:   System: LENOVO (portable) product: 20H3A003CD v: ThinkPad E470c
           Mobo: LENOVO model: 20H3A003CD v: SDK0K09938 WIN
           Bios: LENOVO v: R0DET81W (1.81 ) date: 04/27/2017
CPU:       Dual core Intel Core i5-6200U (-HT-MCP-) cache: 3072 KB
           flags: (lm nx sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx) bmips: 9600
           clock speeds: max: 2800 MHz 1: 1600 MHz 2: 1600 MHz 3: 1600 MHz
           4: 1600 MHz
Graphics:  Card-1: Intel Sky Lake Integrated Graphics bus-ID: 00:02.0
           Card-2: NVIDIA Device 134f bus-ID: 01:00.0
           Display Server: X.Org 1.19.6 drivers: (unloaded: fbdev,vesa) FAILED: nouveau
           Resolution: 1366x768@60.06hz
           GLX Renderer: Mesa DRI Intel HD Graphics 520 (Skylake GT2)
           GLX Version: 3.0 Mesa 18.0.5 Direct Rendering: Yes

I've never configured any specific video drivers -- I definitely can't rule this out as a cause.

Thanks!

James

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#10 2018-12-03 01:28:10

MountainDewManiac
Member
From: Where Mr. Bankruptcy is Prez
Registered: 2013-03-24
Posts: 1,019

Re: External monitors sometimes not detected

Typing:

recover windows password from linux?

into an Internet search engine returns approximately 22,000,000 results. Things change, and not every method will be expected to work with every version of Microsoft Windows - but some probably still will.

Regards,
MDM


Mountain Dew Maniac

How to Ask for Help <=== Click on this link

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#11 2018-12-04 17:25:15

mint4all
Member
From: America
Registered: 2018-08-21
Posts: 71

Re: External monitors sometimes not detected

This info ...

Graphics:  Card-1: Intel Sky Lake Integrated Graphics bus-ID: 00:02.0
           Card-2: NVIDIA Device 134f bus-ID: 01:00.0
           Display Server: X.Org 1.19.6 drivers: (unloaded: fbdev,vesa) FAILED: nouveau
           Resolution: 1366x768@60.06hz

gives us one much-needed clue: the GPU that is powering your external display/monitor/projector, is in fact the "Nvidia Geforce 920MX" notebook processor (see @ https://us.download.nvidia.com/XFree86/ … chips.html ), which requires Nvidia's 384.111 (or better) device/display driver (see @ https://www.nvidia.com/download/driverR … 8737/en-us ) to operate properly. However, linux' "nouveau" driver -- which seems to work ok for most of nvidia's GPUs -- failed to load, and there's no hint of Nvidia's driver being used.

Sooo, i suggest you open the settings manager and look in the "Hardware" section's "Additional Drivers" (iirc) sub-section and check if any of Nvidia's drivers is reported as "installed". If yes, i'd remove & then re-install it. If not installed at all, check to see of the 384.111 driver (or an earlier version) is available, then install that one, do a full shutdown (no suspending, no rebooting), followed by power-on. Once fully booted, please rerun the "xrandr" and 'inxi" commands; then let's inspect what we have ...

PS: the nvidia driver will mess up your boot-splash window, but don't worry about that for now.

Cheers, m4a


Linux Mint 18.3-xfce & Linux Mint 19-xfce  -- Dell Precision T1500 Desktops -- Toshiba Satellite Laptop -- Family & Community Support re. Linux

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#12 2018-12-05 02:47:00

ddwmusic
Member
Registered: 2017-07-23
Posts: 21

Re: External monitors sometimes not detected

OK. Based on 2 suggestions (try 18.10, and deal with drivers) -- I just made a bootable USB of 18.10, and running

inxi -Fxz

shows that nouveau is loading in that environment. So I might just set up my performance environment on the USB stick and use it on the 16th (rather than risk surprises in my main production environment).

I'm not able to test in the media lab right now, but it's promising that the newer OS seems to have better driver support.

Thanks for the tips!

James

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#13 2018-12-05 13:04:05

ddwmusic
Member
Registered: 2017-07-23
Posts: 21

Re: External monitors sometimes not detected

More details: First try with a non-persistent live stick, with the media lab projector, failed. Same result. "inxi -Fxz" on that stick showed nouveau is loading.

So I re-burned the stick with a persistent image (Ubuntu Studio 18,10), installed NVIDIA 390, cold rebooted, and the control panel remembered NVIDIA, but inxi says... it's still using nouveau.

Graphics:
  Device-1: Intel Skylake GT2 [HD Graphics 520] driver: i915 v: kernel 
  bus ID: 00:02.0 
  Device-2: NVIDIA GM108M [GeForce 920MX] driver: nouveau v: kernel 
  bus ID: 01:00.0 
  Display: x11 server: X.Org 1.20.1 driver: modesetting unloaded: fbdev,vesa 
  resolution: 1366x768~60Hz 
  OpenGL: renderer: Mesa DRI Intel HD Graphics 520 (Skylake GT2) 
  v: 4.5 Mesa 18.2.2 direct render: Yes 

At home, using my HDMI TV, no problem (but this never had a problem).

So we are at situation basically unchanged... the TV (which worked before) still works, and the school projector (which didn't work before) still doesn't work (though I should retry tomorrow with the new persistent system).

James

Last edited by ddwmusic (2018-12-05 13:04:41)

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#14 2018-12-08 18:00:14

mint4all
Member
From: America
Registered: 2018-08-21
Posts: 71

Re: External monitors sometimes not detected

Thanks!

So your system works reliably at home -- that's good to know since that rules out a fried hdmi-connector.

So after aaving looked into this further, i'm suspecting that your projector's hdmi-connection is faulty. Has it EVER worked for you (with YOUR thinkpad & model)? Or does it work for everybody else EXCEPT for you? Ime, public venues' equipment gets "abused" quote often, or uses an assortment of dongles & cables frequently thrown together at the last minute.

Put a different way: the hdmi-interface is a smart, bi-directional, synchronous connection; and that projector is not   communicating as it ought to. That's why your system's display manager cannot sense/sniff out what it is attached to. The only workaround i can think of is to use an hdmi-2-vga dongle (with an external power plug) that sells on ebay for ~ $9-12.

Cheers, m4a


Linux Mint 18.3-xfce & Linux Mint 19-xfce  -- Dell Precision T1500 Desktops -- Toshiba Satellite Laptop -- Family & Community Support re. Linux

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#15 2018-12-08 21:45:03

MountainDewManiac
Member
From: Where Mr. Bankruptcy is Prez
Registered: 2013-03-24
Posts: 1,019

Re: External monitors sometimes not detected

mint4all wrote:

So after aaving looked into this further, i'm suspecting that your projector's hdmi-connection is faulty.

Might it just be old? There have been six or seven different versions of the HDMI standard; I think it's officially at 2.1 now, but everything in the chain would have to be "matched" (in other words, no part being of a lesser version than the rest) in order for all features present to work properly.

But I don't know what was introduced when, so this may not be a factor.

Regards,
MDM


Mountain Dew Maniac

How to Ask for Help <=== Click on this link

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#16 2018-12-10 00:18:56

ddwmusic
Member
Registered: 2017-07-23
Posts: 21

Re: External monitors sometimes not detected

mint4all wrote:

Thanks!
So your system works reliably at home -- that's good to know since that rules out a fried hdmi-connector.

So after aaving looked into this further, i'm suspecting that your projector's hdmi-connection is faulty. Has it EVER worked for you (with YOUR thinkpad & model)? Or does it work for everybody else EXCEPT for you? Ime, public venues' equipment gets "abused" quote often, or uses an assortment of dongles & cables frequently thrown together at the last minute.

I've tried HDMI with four different devices:

- TV at home: Works perfectly.
- Projector at school: Not recognized.
- Projector in a bar (for a gig): Not recognized.
- TV in the same bar: Worked perfectly.

The projector at school works perfectly with the Mac workstation at the teacher's desk.

The projector in the bar works perfectly with the VJ's Windows system.

So if I go to the people at the school or the bar and say, "Your cables are faulty or the equipment is too old" or whatever, from their perspective, *my* machine is the odd duck and they would be perfectly justified to ask why Linux can't handle a device that other machines handle just fine.

Put a different way: the hdmi-interface is a smart, bi-directional, synchronous connection; and that projector is not communicating as it ought to. That's why your system's display manager cannot sense/sniff out what it is attached to. The only workaround i can think of is to use an hdmi-2-vga dongle (with an external power plug) that sells on ebay for ~ $9-12.

<editorialRant>Sounds, then, like HDMI is over-engineered to the point of fragility...</editorialRant>

James

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#17 2018-12-14 00:43:56

ddwmusic
Member
Registered: 2017-07-23
Posts: 21

Re: External monitors sometimes not detected

Hmph. Well, I got a HDMI-to-VGA dongle.

Last night, with an old VGA monitor lying around, I got an intermittent connection.

This morning, with a newer VGA monitor in my office, I get nothing at all -- device is totally not recognized, same as before, HDMI "not connected."

Possibly a faulty unit, can't understand why it half worked last night and only 12 hours later, nothing at all.

This is really a pain in the ... something I won't name.

hjh

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#18 2018-12-14 12:33:12

ddwmusic
Member
Registered: 2017-07-23
Posts: 21

Re: External monitors sometimes not detected

Update - I bought a second HDMI-to-VGA dongle, and that one has worked with two separate VGA monitors.

So the first dongle was faulty.

Still annoying but maybe some hope.

hjh

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#19 2018-12-14 17:59:06

mint4all
Member
From: America
Registered: 2018-08-21
Posts: 71

Re: External monitors sometimes not detected

Yikes ... And you're running out of time sad

Sadly to say -- i am running out of google-fu altogether. My last try was to download your thinkpad's user manual. There's a bios option on page 48 that allows a switch beteen the integrated intel-gpu, and a "discrete graphics chip" (whatever THAT means). But it is supposedly only available for AMD-chips. Worth a look, @ page 48? Also check the other settings in the bios-menu's "Display" section.

Very last resort: take your laptop to a "geek-squad" (ie Best Buys) and have them use an hdmi-port scanner. You could have a defective hdmi port after all.

Good luck with your prez -- please accept my apology for not being all that helpful sad

m4a


Linux Mint 18.3-xfce & Linux Mint 19-xfce  -- Dell Precision T1500 Desktops -- Toshiba Satellite Laptop -- Family & Community Support re. Linux

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#20 2018-12-15 01:20:30

ddwmusic
Member
Registered: 2017-07-23
Posts: 21

Re: External monitors sometimes not detected

No, actually, I appreciate all the help. It's been great to discuss it with somebody who has had similar problems.

I'm cautiously optimistic about the second adapter. The first one, testing at home, would drop the connection frequently -- but the second one, testing at home with the same monitor, worked perfectly. It's pretty obvious -- same computer, same monitor, different adapter, the different results must be because of the adapter (therefore, just bad luck that the first one was broken). But, yesterday morning when I tested, I didn't have the second adapter -- missing that data point.

It's disappointing that HDMI support seems to be lagging behind in Ubuntu, but VGA is an acceptable workaround for me. So I think we can consider this thread closed :-)

Thanks again!

hjh

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