Discussion:
upgrade from 16.04 to 18.04 today, MKV no longer playing correctly in VLC
(too old to reply)
Runner
2020-09-10 20:57:01 UTC
Permalink
Just updated my system today from 16.04 to 18.04 and my MKV's no longer
play correctly, blocky and tearing. Have tried uninstalling and
reinstalling VLC. Also tried a VLC appimage for 18.04, still blocky.
Any help to resolve welcome. Thank you.
Runner
2020-09-10 21:07:57 UTC
Permalink
Post by Runner
Just updated my system today from 16.04 to 18.04 and my MKV's no longer
play correctly, blocky and tearing.  Have tried uninstalling and
reinstalling VLC.  Also tried a VLC appimage for 18.04, still blocky.
Any help to resolve welcome.  Thank you.
Just to follow up, I tried mpv media player and it plays them perfectly,
but I would still like to use VLC.
Runner
2020-09-10 21:09:55 UTC
Permalink
Post by Runner
Post by Runner
Just updated my system today from 16.04 to 18.04 and my MKV's no
longer play correctly, blocky and tearing.  Have tried uninstalling
and reinstalling VLC.  Also tried a VLC appimage for 18.04, still
blocky. Any help to resolve welcome.  Thank you.
Just to follow up, I tried mpv media player and it plays them perfectly,
but I would still like to use VLC.
Follow up yet again: VLC is no longer playing any MP4 files without
being blocky/ green screens too.
Paul
2020-09-10 21:44:01 UTC
Permalink
Post by Runner
Post by Runner
Post by Runner
Just updated my system today from 16.04 to 18.04 and my MKV's no
longer play correctly, blocky and tearing. Have tried uninstalling
and reinstalling VLC. Also tried a VLC appimage for 18.04, still
blocky. Any help to resolve welcome. Thank you.
Just to follow up, I tried mpv media player and it plays them
perfectly, but I would still like to use VLC.
Follow up yet again: VLC is no longer playing any MP4 files without
being blocky/ green screens too.
Check whether any kind of hardware overlay is selected for the
playback process. "Green" used to be associated with an overlay
problem.

Need more details, to reproduce...

Paul
Big Bad Bob
2020-09-16 05:44:04 UTC
Permalink
Post by Runner
Post by Runner
Just updated my system today from 16.04 to 18.04 and my MKV's no
longer play correctly, blocky and tearing.  Have tried uninstalling
and reinstalling VLC.  Also tried a VLC appimage for 18.04, still
blocky. Any help to resolve welcome.  Thank you.
Just to follow up, I tried mpv media player and it plays them
perfectly, but I would still like to use VLC.
 Follow up yet again: VLC is no longer playing any MP4 files without
being blocky/ green screens too.
I'm curious what your video output is. I generally have good luck with
SDL and XVideo. However, depending on your display card, different
things may work better. Also might be a bug.

yeah, upgrades are HIGHLY overated. And sometimes, not just bugs, but
FEATURE CREEP. Ew.
--
(aka 'Bombastic Bob' in case you wondered)

'Feeling with my fingers, and thinking with my brain' - me

'your story is so touching, but it sounds just like a lie'
"Straighten up and fly right"
Paul
2020-09-10 21:40:31 UTC
Permalink
Post by Runner
Post by Runner
Just updated my system today from 16.04 to 18.04 and my MKV's no
longer play correctly, blocky and tearing. Have tried uninstalling
and reinstalling VLC. Also tried a VLC appimage for 18.04, still
blocky. Any help to resolve welcome. Thank you.
Just to follow up, I tried mpv media player and it plays them perfectly,
but I would still like to use VLC.
While this is a windows page, there is a suggestion that
blocky playback in VLC is due to the selection of
"Hardware Accelerated Decoding". Check the setting in
your Preferences and play with it a bit and retest.

https://windowsreport.com/vlc-pixelated/

You could be using Nouveau for your NVidia video card or
you could be using the Restricted Driver selection
provided by NVidia (binary blob). The vintage of your
card affects acceleration options (i.e. whether the
video SIP has MP4 of H.264 or H.265 or MPEG2 or whatever).
With Nouveau, there might be some emulated decoding and
a few things accelerated (hardware scaler).

There are a *lot* of variables in there.

The MKV is the "container". There are CODECs inside for
the video stream and the audio stream. The accelerated
decoding is for the CODEC used. Hardware tends to support
Hollywood formats. Ogg/Theora would not be something
NVidia or AMD would be in a rush to put in shader decoders
or whatever.

To debug your situation, we'd need to know

MKV video - what codecs were inside, specifically the video stream ?
An application like "ffplay" from "ffmpeg" would tell you.

ffplay mymovie.MKV

video card ?
video driver used to make video card work ? Use Inxi to get details.

vlc preferences used ?

You could compare how MPV video player is playing your
video (maybe unaccelerated, nothing but CPU for decoder).
Does MPV have preferences ?

The Nouveau people tell you a bit about what work they've
done to harness the SIP in the GPU.

https://nouveau.freedesktop.org/wiki/VideoAcceleration/

NVidia have some details for their hardware. AMD
should have a similar page. NVidia has NVdec, NVenc, CUDA (shader)
as examples. The FreeDesktop page gives the Linux names of
some of the subsystems in software, used for video playback.

https://developer.nvidia.com/video-encode-decode-gpu-support-matrix

The very first hardware acceleration feature was IDCT (Inverse Discrete
Cosine Transform), which is a part of working in the frequency domain,
with macroblocks. A lot of the video formats work in the frequency
domain, throwing away sharpness to decrease file size. In modern times,
snooty developers have stopped using IDCT - presumably the processor
is now faster at it than consulting some video card, so the
shoe has shifted to the other foot now. But at one time, that
was our "acceleration" - it's just a tiny portion of the decoding
process. The NVidia chart above, the *entire* chain is in hardware
now, but not for every codec out there. This means, if all was working
as well as it should, for a few movies the only CPU needed
would be to fetch a block of data from the hard drive
every once in a while (close to 0% CPU). When the CPU does the
decoding, it might take 30% to do the job. In the old days,
it wasn't uncommon for CPU to range from 10% (very good quality
software) to 100% (CPU pegged because software was so bad at it).
There's more CPU power available today, so it's less likely to
rail. All that the hardware acceleration does, is annoy the
developers :-)

Paul
Runner
2020-09-10 23:01:01 UTC
Permalink
Post by Paul
Post by Runner
Post by Runner
Just updated my system today from 16.04 to 18.04 and my MKV's no
longer play correctly, blocky and tearing.  Have tried uninstalling
and reinstalling VLC.  Also tried a VLC appimage for 18.04, still
blocky. Any help to resolve welcome.  Thank you.
Just to follow up, I tried mpv media player and it plays them
perfectly, but I would still like to use VLC.
While this is a windows page, there is a suggestion that
blocky playback in VLC is due to the selection of
"Hardware Accelerated Decoding". Check the setting in
your Preferences and play with it a bit and retest.
https://windowsreport.com/vlc-pixelated/
Thank you, this did the trick! Not only that, but I stuck with the
Appimage and then used AppImageLauncher to integrate.

Before upgrading, I DID make a backup of the existing system first just
in case I run into non-fixable problems.
Big Bad Bob
2020-09-16 05:46:08 UTC
Permalink
Post by Paul
Post by Runner
Post by Runner
Just updated my system today from 16.04 to 18.04 and my MKV's no
longer play correctly, blocky and tearing.  Have tried uninstalling
and reinstalling VLC.  Also tried a VLC appimage for 18.04, still
blocky. Any help to resolve welcome.  Thank you.
Just to follow up, I tried mpv media player and it plays them
perfectly, but I would still like to use VLC.
While this is a windows page, there is a suggestion that
blocky playback in VLC is due to the selection of
"Hardware Accelerated Decoding". Check the setting in
your Preferences and play with it a bit and retest.
https://windowsreport.com/vlc-pixelated/
You could be using Nouveau for your NVidia video card or
you could be using the Restricted Driver selection
provided by NVidia (binary blob). The vintage of your
card affects acceleration options (i.e. whether the
video SIP has MP4 of H.264 or H.265 or MPEG2 or whatever).
With Nouveau, there might be some emulated decoding and
a few things accelerated (hardware scaler).
There are a *lot* of variables in there.
The MKV is the "container". There are CODECs inside for
the video stream and the audio stream. The accelerated
decoding is for the CODEC used. Hardware tends to support
Hollywood formats. Ogg/Theora would not be something
NVidia or AMD would be in a rush to put in shader decoders
or whatever.
To debug your situation, we'd need to know
MKV video - what codecs were inside, specifically the video stream ?
            An application like "ffplay" from "ffmpeg" would tell you.
            ffplay mymovie.MKV
video card ?
video driver used to make video card work ?  Use Inxi to get details.
vlc preferences used ?
You could compare how MPV video player is playing your
video (maybe unaccelerated, nothing but CPU for decoder).
Does MPV have preferences ?
The Nouveau people tell you a bit about what work they've
done to harness the SIP in the GPU.
https://nouveau.freedesktop.org/wiki/VideoAcceleration/
NVidia have some details for their hardware. AMD
should have a similar page. NVidia has NVdec, NVenc, CUDA (shader)
as examples. The FreeDesktop page gives the Linux names of
some of the subsystems in software, used for video playback.
https://developer.nvidia.com/video-encode-decode-gpu-support-matrix
if possible, use the NVidia driver. Fewer problems, updated hardware
support, etc.. I've been using NVidia on Linux and FreeBSD for a long
time. Best to use module-assistant and build the NVidia driver+wrapper
and install it.

or at least that's what I would do
Runner
2020-09-19 17:13:54 UTC
Permalink
On 9/16/20 1:46 AM, Big Bad Bob wrote:
  Best to use module-assistant and build the NVidia driver+wrapper
Post by Big Bad Bob
and install it.
or at least that's what I would do
Wish I knew how to do this. I'm familiar with Ubuntu basics, but that's
about it.
Jonathan N. Little
2020-09-19 18:07:19 UTC
Permalink
Post by Runner
  Best to use module-assistant and build the NVidia driver+wrapper
Post by Big Bad Bob
and install it.
or at least that's what I would do
Wish I knew how to do this.  I'm familiar with Ubuntu basics, but that's
about it.
Why not just go to Software & Updates, go to the Additional Drivers tab
and if you re using the default crappy Nouveau driver select the newer,
better, nVidia propriety driver.
--
Take care,

Jonathan
-------------------
LITTLE WORKS STUDIO
http://www.LittleWorksStudio.com
Runner
2020-09-19 21:00:48 UTC
Permalink
Post by Jonathan N. Little
Post by Runner
  Best to use module-assistant and build the NVidia driver+wrapper
Post by Big Bad Bob
and install it.
or at least that's what I would do
Wish I knew how to do this.  I'm familiar with Ubuntu basics, but that's
about it.
Why not just go to Software & Updates, go to the Additional Drivers tab
and if you re using the default crappy Nouveau driver select the newer,
better, nVidia propriety driver.
Thanks, just tried it. All I get is "No additional drivers available"
and "No proprietary drivers are in use". I take it from that that I am
not using better drivers.
Jonathan N. Little
2020-09-20 11:18:20 UTC
Permalink
Post by Jonathan N. Little
   Best to use module-assistant and build the NVidia driver+wrapper
Post by Big Bad Bob
and install it.
or at least that's what I would do
Wish I knew how to do this.  I'm familiar with Ubuntu basics, but that's
about it.
Why not just go to Software & Updates, go to the Additional Drivers tab
and if you re using the default crappy Nouveau driver select the newer,
better, nVidia propriety driver.
Thanks, just tried it.  All I get is "No additional drivers available"
and "No proprietary drivers are in use".  I take it from that that I am
not using better drivers.
Well I hadn't read the whole thread, but are you sure you are using a
nVidia GPU?

lspci | grep VGA

If you are you'll get something like this:
lspci | grep VGA
01:00.0 VGA compatible controller: NVIDIA Corporation GK107 [GeForce GTX
650] (rev a1)

and if you have a nVidia driver installed you will have the nvidia-smi tool

nvidia-smi
Sun Sep 20 07:09:11 2020
+-----------------------------------------------------------------------------+
| NVIDIA-SMI 384.130 Driver Version: 384.130
|
|-------------------------------+----------------------+----------------------+
| GPU Name Persistence-M| Bus-Id Disp.A | Volatile
Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap| Memory-Usage | GPU-Util
Compute M. |
|===============================+======================+======================|
| 0 GeForce GTX 650 Off | 00000000:01:00.0 N/A |
N/A |
| 21% 19C P8 N/A / N/A | 311MiB / 972MiB | N/A
Default |
+-------------------------------+----------------------+----------------------+

+-----------------------------------------------------------------------------+
| Processes: GPU
Memory |
| GPU PID Type Process name Usage
|
|=============================================================================|
| 0 Not Supported
|
+-----------------------------------------------------------------------------+

Also IIRC Additional Drivers will not find proprietary drivers unless
you enable the restricted repository
--
Take care,

Jonathan
-------------------
LITTLE WORKS STUDIO
http://www.LittleWorksStudio.com
Runner
2020-09-20 14:12:13 UTC
Permalink
Post by Jonathan N. Little
Post by Jonathan N. Little
   Best to use module-assistant and build the NVidia driver+wrapper
Post by Big Bad Bob
and install it.
or at least that's what I would do
Wish I knew how to do this.  I'm familiar with Ubuntu basics, but that's
about it.
Why not just go to Software & Updates, go to the Additional Drivers tab
and if you re using the default crappy Nouveau driver select the newer,
better, nVidia propriety driver.
Thanks, just tried it.  All I get is "No additional drivers available"
and "No proprietary drivers are in use".  I take it from that that I am
not using better drivers.
Well I hadn't read the whole thread, but are you sure you are using a
nVidia GPU?
lspci | grep VGA
lspci | grep VGA
01:00.0 VGA compatible controller: NVIDIA Corporation GK107 [GeForce GTX
650] (rev a1)
Here is what the card is:

1:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI]
RV670 [Radeon HD 3870]
Post by Jonathan N. Little
and if you have a nVidia driver installed you will have the nvidia-smi tool
nvidia-smi
Sun Sep 20 07:09:11 2020
+-----------------------------------------------------------------------------+
| NVIDIA-SMI 384.130 Driver Version: 384.130
|
|-------------------------------+----------------------+----------------------+
| GPU Name Persistence-M| Bus-Id Disp.A | Volatile
Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap| Memory-Usage | GPU-Util
Compute M. |
|===============================+======================+======================|
| 0 GeForce GTX 650 Off | 00000000:01:00.0 N/A |
N/A |
| 21% 19C P8 N/A / N/A | 311MiB / 972MiB | N/A
Default |
+-------------------------------+----------------------+----------------------+
+-----------------------------------------------------------------------------+
| Processes: GPU
Memory |
| GPU PID Type Process name Usage
|
|=============================================================================|
| 0 Not Supported
|
+-----------------------------------------------------------------------------+
Also IIRC Additional Drivers will not find proprietary drivers unless
you enable the restricted repository
Jonathan N. Little
2020-09-20 14:53:18 UTC
Permalink
<snip>
Post by Runner
Post by Jonathan N. Little
Well I hadn't read the whole thread, but are you sure you are using a
nVidia GPU?
lspci | grep VGA
lspci | grep VGA
01:00.0 VGA compatible controller: NVIDIA Corporation GK107 [GeForce GTX
650] (rev a1)
1:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI]
RV670 [Radeon HD 3870]
So the answer is no. Not sure what all the talk about the nVidia drivers
was about. ATI nouveau drivers are generally okay and much better than
they are for nVidia. But that said ATI loves to drop support for their
legacy cards and the 3870 is over a decade old. Had some systems with
ATI onboard gpus at the library years ago break after a kernel update
and ATI had orphan that chipset in their drivers so I remedied with some
cheap nVidia cards.
--
Take care,

Jonathan
-------------------
LITTLE WORKS STUDIO
http://www.LittleWorksStudio.com
Runner
2020-09-20 15:16:24 UTC
Permalink
Post by Jonathan N. Little
<snip>
Post by Runner
Post by Jonathan N. Little
Well I hadn't read the whole thread, but are you sure you are using a
nVidia GPU?
lspci | grep VGA
lspci | grep VGA
01:00.0 VGA compatible controller: NVIDIA Corporation GK107 [GeForce GTX
650] (rev a1)
1:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI]
RV670 [Radeon HD 3870]
So the answer is no. Not sure what all the talk about the nVidia drivers
was about. ATI nouveau drivers are generally okay and much better than
they are for nVidia. But that said ATI loves to drop support for their
legacy cards and the 3870 is over a decade old. Had some systems with
ATI onboard gpus at the library years ago break after a kernel update
and ATI had orphan that chipset in their drivers so I remedied with some
cheap nVidia cards.
And not the greatest card either most likely, as you say also, due to
age. I run dual boot and Win 10 OS also with a program called Affinity
Photo, which is a Photoshop like program with one time purchase fee
unlike Photoshop who now requires monthly subscription. I switched to
it for that reason, but the longer I do work on imagery, the greater the
chance my screen will go black and I have to reboot. I think the card
is a bit too old now, but lack funds for something that wouldn't crash
so I just limit my time and save often.

The biggest problem I've had in Ubuntu is random, sudden total freeze
where I have to reboot. Have not had it happen since the upgrade to
18.04, but I'm almost sure a freeze will occur one random day soon.
Jonathan N. Little
2020-09-20 15:27:07 UTC
Permalink
Post by Runner
And not the greatest card either most likely, as you say also, due to
age.  I run dual boot and Win 10 OS also with a program called Affinity
Photo, which is a Photoshop like program with one time purchase fee
unlike Photoshop who now requires monthly subscription.  I switched to
it for that reason, but the longer I do work on imagery, the greater the
chance my screen will go black and I have to reboot.  I think the card
is a bit too old now, but lack funds for something that wouldn't crash
so I just limit my time and save often.
The biggest problem I've had in Ubuntu is random, sudden total freeze
where I have to reboot.  Have not had it happen since the upgrade to
18.04, but I'm almost sure a freeze will occur one random day soon.
I have not seen Linux "freeze" a system requiring a reboot in over a
decade. Are you sure it is really hung or just some application hung
like Firefox on some really poorly coded website (Yes I'm talking about
you Farcebook). Can you CTRL+ALT+F2 log into a virtual terming and kill
the rogue process? BTW the only "freezes" that halt the OS in Linux I
have seen in modern times war 99.99% hardware failure.
--
Take care,

Jonathan
-------------------
LITTLE WORKS STUDIO
http://www.LittleWorksStudio.com
Runner
2020-09-20 17:38:09 UTC
Permalink
Post by Jonathan N. Little
Post by Runner
And not the greatest card either most likely, as you say also, due to
age.  I run dual boot and Win 10 OS also with a program called Affinity
Photo, which is a Photoshop like program with one time purchase fee
unlike Photoshop who now requires monthly subscription.  I switched to
it for that reason, but the longer I do work on imagery, the greater the
chance my screen will go black and I have to reboot.  I think the card
is a bit too old now, but lack funds for something that wouldn't crash
so I just limit my time and save often.
The biggest problem I've had in Ubuntu is random, sudden total freeze
where I have to reboot.  Have not had it happen since the upgrade to
18.04, but I'm almost sure a freeze will occur one random day soon.
I have not seen Linux "freeze" a system requiring a reboot in over a
decade. Are you sure it is really hung or just some application hung
like Firefox on some really poorly coded website (Yes I'm talking about
you Farcebook). Can you CTRL+ALT+F2 log into a virtual terming and kill
the rogue process? BTW the only "freezes" that halt the OS in Linux I
have seen in modern times war 99.99% hardware failure.
When I have the freeze, I can either reboot by pressing and holding
the desktop power button, or I can do REISUB. When I get to B, the
system reboots. Otherwise, nothing responds. It doesn't happen often,
but seems to, for example, if I am playing a movie on one screen while
viewing something else on the other (I run two monitors). I could also
be writing an email to someone on one screen, while I have Firefox open
to a website on the other. Sometimes I can get a freezing then, but
even that's not all the time.
Jonathan N. Little
2020-09-20 19:44:16 UTC
Permalink
Post by Jonathan N. Little
Post by Runner
And not the greatest card either most likely, as you say also, due to
age.  I run dual boot and Win 10 OS also with a program called Affinity
Photo, which is a Photoshop like program with one time purchase fee
unlike Photoshop who now requires monthly subscription.  I switched to
it for that reason, but the longer I do work on imagery, the greater the
chance my screen will go black and I have to reboot.  I think the card
is a bit too old now, but lack funds for something that wouldn't crash
so I just limit my time and save often.
The biggest problem I've had in Ubuntu is random, sudden total freeze
where I have to reboot.  Have not had it happen since the upgrade to
18.04, but I'm almost sure a freeze will occur one random day soon.
I have not seen Linux "freeze" a system requiring a reboot in over a
decade. Are you sure it is really hung or just some application hung
like Firefox on some really poorly coded website (Yes I'm talking about
you Farcebook). Can you CTRL+ALT+F2 log into a virtual terming and kill
the rogue process? BTW the only "freezes" that halt the OS in Linux I
have seen in modern times war 99.99% hardware failure.
 When I have the freeze, I can either reboot by pressing and holding the
desktop power button, or I can do REISUB.  When I get to B, the system
reboots.  Otherwise, nothing responds.  It doesn't happen often, but
seems to, for example, if I am playing a movie on one screen while
viewing something else on the other (I run two monitors).  I could also
be writing an email to someone on one screen, while I have Firefox open
to a website on the other.  Sometimes I can get a freezing then, but
even that's not all the time.
But that does not mean you have a hung system. CTRL+ALT+F2 and you can
log into a virtual terminal. You can even kill your desktop session. If
you are still using lighdm

sudo systemctl restart lightdm

or GNOME

sudo systemctl restart gdm

and you will be back at the log in screen

Desktop can crash, the video driver can crash, and Linux keeps chugging
on. Not Windows where bad apps can bring the system down...although
Windows is better at that now..
--
Take care,

Jonathan
-------------------
LITTLE WORKS STUDIO
http://www.LittleWorksStudio.com
Runner
2020-09-21 15:19:12 UTC
Permalink
Post by Jonathan N. Little
But that does not mean you have a hung system. CTRL+ALT+F2 and you can
log into a virtual terminal. You can even kill your desktop session. If
you are still using lighdm
Oddly enough, ever since upgrading from 16.04 to 18.04 a couple of weeks
ago, ctrl-alt-t barely works to even bring up a terminal and I often
have to go into search to bring it up. I have even tried tried using
CompizConfig to designate as such, but still doesn't work much of the
time.
Post by Jonathan N. Little
sudo systemctl restart lightdm
or GNOME
sudo systemctl restart gdm
and you will be back at the log in screen
Desktop can crash, the video driver can crash, and Linux keeps chugging
on. Not Windows where bad apps can bring the system down...although
Windows is better at that now..
Taking note of all of this the next time I get a freeze so I can try it.
Wes Newell
2020-09-21 15:32:19 UTC
Permalink
Post by Runner
Oddly enough, ever since upgrading from 16.04 to 18.04 a couple of weeks
ago, ctrl-alt-t barely works to even bring up a terminal and I often
have to go into search to bring it up.  I have even tried tried using
CompizConfig to designate as such, but still doesn't work much of the time.
Go to keyboard settings and you can create/delete all the shortcuts you
want.
--
http://wesnewell.ddns.net
https://github.com/wesnewell/Functionality
Runner
2020-09-21 16:18:59 UTC
Permalink
Post by Wes Newell
Post by Runner
Oddly enough, ever since upgrading from 16.04 to 18.04 a couple of
weeks ago, ctrl-alt-t barely works to even bring up a terminal and I
often have to go into search to bring it up.  I have even tried tried
using CompizConfig to designate as such, but still doesn't work much
of the time.
Go to keyboard settings and you can create/delete all the shortcuts you
want.
Tried that. Deleting the terminal designation and then adding again.
Same result. I have also disabled either/or the designation in Compiz/
keyboard shortcuts so they wouldn't interfere with one another. Same
result. Lastly, I installed konsole and tried to set up a shortcut. In
all cases, sometimes terminal will open but often not and I end up right
clicking and choosing "Open Terminal" which works as long as I do it on
the desktop.

Paul
2020-09-21 01:46:53 UTC
Permalink
Post by Jonathan N. Little
Post by Runner
And not the greatest card either most likely, as you say also, due to
age. I run dual boot and Win 10 OS also with a program called Affinity
Photo, which is a Photoshop like program with one time purchase fee
unlike Photoshop who now requires monthly subscription. I switched to
it for that reason, but the longer I do work on imagery, the greater the
chance my screen will go black and I have to reboot. I think the card
is a bit too old now, but lack funds for something that wouldn't crash
so I just limit my time and save often.
The biggest problem I've had in Ubuntu is random, sudden total freeze
where I have to reboot. Have not had it happen since the upgrade to
18.04, but I'm almost sure a freeze will occur one random day soon.
I have not seen Linux "freeze" a system requiring a reboot in over a
decade. Are you sure it is really hung or just some application hung
like Firefox on some really poorly coded website (Yes I'm talking about
you Farcebook). Can you CTRL+ALT+F2 log into a virtual terming and kill
the rogue process? BTW the only "freezes" that halt the OS in Linux I
have seen in modern times war 99.99% hardware failure.
When I have the freeze, I can either reboot by pressing and holding the
desktop power button, or I can do REISUB. When I get to B, the system
reboots. Otherwise, nothing responds. It doesn't happen often, but
seems to, for example, if I am playing a movie on one screen while
viewing something else on the other (I run two monitors). I could also
be writing an email to someone on one screen, while I have Firefox open
to a website on the other. Sometimes I can get a freezing then, but
even that's not all the time.
There's a couple things you can do.

From a second machine, try pinging the IP address of the hung machine.
If it responds to the ping, it isn't hung. It then suggests a display
subsystem failure. In the following picture "3" isn't broken, because
it answered the ping OK, and then you need to figure out how to run
"3", without a working display.

[192.168.1.2] [192.168.1.3]

working broken

ping 192.168.1.3 ==> ICMP, ACK --+
|
<===================+

The second thing I do, is my Test Machine has a serial port on the
SuperI/O chip. This makes it ttyS0 (fixed address), from an addressing
perspective, whereas USB can "move around" numerically. On the kernel
boot line, I use

quiet splash <=== remove this part

console=ttyS0,57600N8 <=== says to make the serial port, the "Console", at 57.6 Kbaud

From this machine, I log in using putty, set the baud rate to match,
and then I can log into the other machine (the equivalent of "3").

I could type "dmesg" and look for any messages about video card failures.

Or look in /var/log for Xorg results.

To set up a serial port connection between two computers, you need
a "null modem" adapter plug, which connects rx to tx and tx to rx
(crossover). And my adapter plug, in the middle of the cable run,
actually has "null modem" printed right in the plastic of the shell.

There are other ways to remote into computers, using stuff
like "ssh". But that's not my style. I want interfaces
so primitive, "they just work". There are also things
like TeamViewer or VNC. You can also run XOrg sessions remotely.
I used to display X11 on a Macintosh, using MacX, then connect
to port 6000 on my Unix box at work. And do a few CAD things
(slowly...). But for me today, the serial port is enough to get
the job done. I just want to look at some logs, if I can find them.

Paul
Jonathan N. Little
2020-09-21 02:03:44 UTC
Permalink
There are other ways to remote into computers, using stuff like
"ssh". But that's not my style.
Well I find ssh gets the job done.
I want interfaces so primitive, "they just work". There are also
things like TeamViewer or VNC. You can also run XOrg sessions
remotely. I used to display X11 on a Macintosh, using MacX, then
connect to port 6000 on my Unix box at work. And do a few CAD things
(slowly...). But for me today, the serial port is enough to get the
job done. I just want to look at some logs, if I can find them.
--
Take care,

Jonathan
-------------------
LITTLE WORKS STUDIO
http://www.LittleWorksStudio.com
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