lagging/choppy video on external monitor after upgrade

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lagging/choppy video on external monitor after upgrade

Postby Rich » 2019-11-19 15:27

Several weeks ago, I upgraded the system on my Dell laptop from 9/Stretch to 10/Buster. With v.9, I could connect my Sony TV to the HDMI port and get good quality video on the TV. After upgrading to v.10, I now get very choppy video with any stream that has a lot of rapid motion, e.g., hockey or soccer. The quality of still images is still high, and the quality of the audio is high.

Anyone have advice on this problem?

... Rich
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Re: lagging/choppy video on external monitor after upgrade

Postby Head_on_a_Stick » 2019-11-23 11:45

We need to know the desktop environment (if any) along with your video hardware and drivers.

If this is an Intel system then I would recommend enabling xserver-xorg-video-intel with the TearFree option instead of the modesetting driver (which has no such option, sadly). NVIDIA users can take advantage of their composition pipeline but I don't help heathens.
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Re: lagging/choppy video on external monitor after upgrade

Postby Rich » 2019-11-26 00:55

Thanks for the reply, Head.
I've been trying to do some homework on the TearFree option, but I still haven't come across what I need to know - like exactly where do I set TearFree = true (?)
Along the way, I came across an article that recommended just removing xserver-xorg-video-intel entirely. I tried that, but it didn't help, so I restored that package.

As for your comments/queries:
The machine is a Dell E6430 Latitude laptop. I've been feeding the monitor output to my TV via the HDmi port. It was running Debian v9.9 just fine. When I upgraded to Debian v.10, everything still seemed fine except for this problem with rapid motion on the TV.
I know little about video, so I don't know what's useful to know other than the above.
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Re: lagging/choppy video on external monitor after upgrade

Postby Dai_trying » 2019-11-26 07:41

I have an xorg.conf file placed in /etc/X11/xorg.conf that contains just the below
Code: Select all
Section "Device"
   Identifier  "Intel Graphics"
   Driver      "intel"
   Option      "AccelMethod" "sna"
   Option      "TearFree" "true"
EndSection


and that does the trick for me.
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Re: lagging/choppy video on external monitor after upgrade

Postby Rich » 2019-11-27 01:10

This looksabout like what I need, but I couldn't get it to work properly.
The laptop has no xorg.conf file, except for what I take to be a sample in the /usr/share/doc/xserver-xorg-video-intel directory. I used that sample and your xorg.conf, Dai, to create the following xorg.conf in the /etc/X11 directory:

Code: Select all
Section "Device"
  Identifier "Intel"
  Driver "intel"
  Option "AccelMethod" "sna"
  Option "TearFree" "true"
EndSection


The machine would not boot properly with this xorg.conf. The boot process stalled at a command line prompt instead of continuing to install X and the GUI.
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Re: lagging/choppy video on external monitor after upgrade

Postby Dai_trying » 2019-11-27 07:53

I have not seen anywhere that you have confirmed you have intel graphics, the Dell E6430 could have either Intel or Nvidia so we are still guessing at this point.
If you do have Intel then why not try using the identifier that I have in my example? I know mine works on my E5470 (also worked on Inspiron 15-3552), and I don't know if changing the identifier from "Intel Graphics" to just "Intel" would make a difference.

And I presume when you say
The boot process stalled at a command line prompt instead of continuing to install X and the GUI.
you actually mean "The boot process stalled at a command line prompt instead of continuing to load X and the GUI."
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Re: lagging/choppy video on external monitor after upgrade

Postby Rich » 2019-12-01 23:07

You are right, I didn't confirm that the system is using Intel graphics. I was going on the fact that the package xserver-xorg-video-intel had been installed. Bad assumption.
xserver-xorg-video-nouveau is also installed. I did not realize that that belongs to nvidia.
lshw says that the hardware is nvidia, and lsmod says that a video driver named nouveau is in use.

So it looks like you've caught the problem. Do you happen to know what the fix might be for an nvidia system ;-)

And you are correct in presuming that I meant to say "...continuing to load X ...." Of course xorg, xserver-xorg, and many other X-related packages have been installed.
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Re: lagging/choppy video on external monitor after upgrade

Postby Dai_trying » 2019-12-02 08:23

The first thing you need to do is to delete the xorg.conf that I advised earlier, that was for Intel only and would likely cause your system to not boot rather than fixing it. After that I would reboot to ensure system is clean.

I seem to recall somebody in the forum advising a method to force nouveau driver as opposed to modesetting for nvidia but I cannot re-find that post or give you best advice on it, hopefully somebody else will be able to advise better for that. There is some advise in this post that might help.
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Re: lagging/choppy video on external monitor after upgrade

Postby Rich » 2019-12-02 15:08

I deleted the xorg.conf, and things are back to normal (sigh).

Apparently, the nouveau driver is being used. lshw reports:

Code: Select all
product: GF108GLM (NVS 5200 M)
vendor: NVIDIA Corporation
   ...

configuration: driver=nouveau latency=0


I skimmed through the posting you provided. I'll have to read it more carefully, but I think I'm in over my head on this one.

Thanks for your help so far. Back to doing my homework on this one ....
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