6 ms·

It's like the "oh no, X11 suffers from tearing video" problem that they pull out all the time. (A) I have no idea what "video tear" is and (B) I play video all

by rwmj 1y ago

It's like the "oh no, X11 suffers from tearing video" problem that they pull out all the time. (A) I have no idea what "video tear" is and (B) I play video all the time on my crappy laptop running X11 and it seems fine for me. But can I ssh to my remote server and run emacs or another program completely transparently yet with Wayland? Nope. I do that with X11 continuously.

toast0 1y ago
I've seen video tearing on X. Usually it doesn't happen, often it's hard to notice anyway; and when it did happen and was annoying, I just was missing some setting or other. No big deal.
ndiddy 1y ago
> But can I ssh to my remote server and run emacs or another program completely transparently yet with Wayland? Nope. Yes, you can! Waypipe came out 6 years ago. Its express purpose is to make a Wayland equivalent to ssh -X. https://gitlab.freedesktop.org/mstoeckl/waypipe/ https://gitlab.freedesktop.org/mstoeckl/waypipe/
- aragilar 1y ago
  Except: 1. It's Wayland-to-Wayland (which means you're much more limited to where it can run than X-to-X, where's the MacOS or Windows or BSD Wayland build?). 2. It's not integrated with ssh (X forwarding is part of the protocol). 3. You need it on both the client and the server, so you need to work out how to get it onto the server.
nullc 1y ago
If someone shows it to you, you'll recognize it. It's when one frame shows part of the prior frame and part of the next. It's most visible in moderate speed horizontal pans as an interruption in vertical lines in the picture. It's nice to not have tearing. But IMO the functionality loss vs X11 isn't worth it for anything but a dedicated media playback/editing device.
- simoncion 1y ago
  > It's nice to not have tearing. If you're running AMD hardware, try enabling the TearFree option. [0] I've been using this for years and years and years and it works fine. [0] See this for a config file you could plop into place: <https://news.ycombinator.com/item?id=44375247 https://news.ycombinator.com/item?id=44375247>
kiwijamo 1y ago
I used to see it all the time on X11. I'd see it on YouTube/Firefox. I'd see it on VLC. I'd see it on MPV. Any video player, playing any fast paced video you'll see X11 struggle to keep up with drawing full frames that it'd just give up and draw half of one frame and another half of another frame and call it a day. The Intel driver luckily had an xorg.conf setting I could add to make this less of an issue -- I guess it'd turn on some internal Intel driver logic to skip frames or something else if it wasn't able to draw the entire video frame in time for display. However as soon as Debian made Wayland the default this issue 100% disappared and I no longer needed to edit a conf file to make my display work correctly. This is hands-down the singular reason I love Wayland. It just works without any faffing around as Windows, MacOS, etc has done since the mid 1990's. Wayland has achieved more in 5 years than X11 has done in the last 25 years.
- kelnos 1y ago
  So basically what you are saying is that they could have changed a default in a config file somewhere, 5 minutes of work, but instead they decided to spend hundreds (thousands?) of person-years building something new from scratch? And that's a good thing? Oof.
  - kiwijamo 1y ago
    I assume there's a reason Intel didn't make that particular setting the default in their x11 drivers. While it certainly fixed the screen tearing issue, I presume there was some tradeoff which made some other feature worse off. Wayland however I assume is already built so it doesn't need the driver to implement some workaround to fix it, it's already designed to correctly handle video output by ensuring only the full frame is rendered every single frame.
    - LionEgo 1y ago
      > To summarise, the downsides are that it requires more memory, and that it reduces throughput and adds latency (except when there’s already a compositor or a vblank-synced fullscreen display). https://unix.stackexchange.com/questions/518362/whats-the-downside-to-tearfree-with-intel-graphics https://unix.stackexchange.com/questions/518362/whats-the-do... I think the extra requirements aren't a problem on modern cards. However on lower end devices e.g. the older intel iGPUs, I could see this becoming an issue.
ginko 1y ago
Worst was with the discussion about Wayland having extra latency on mouse pointer movements. The explanation there was that X11 used HW pointer device that got updated as soon as there was a change but that might lead to gasp occasional pointer tearing. So better add a couple ms of latency to everything in Wayland and sample the mouse pointer position once per frame. FWIW, I do see screen tearing on my X11 multi-monitor setup. I just don't care.
- simoncion 1y ago
  > FWIW, I do see screen tearing on my X11 multi-monitor setup. I just don't care. If you ever get really bored one day, and you have nothing else to do, and you're using AMD/ATi hardware, try enabling the TearFree option for your video card driver. Something like Section "Device" Identifier "AMD" Driver "amdgpu" Option "TearFree" "on" EndSection in a new .conf file in '/etc/X11/xorg.conf.d' and a restart of your display server(s) should do the trick. It works fine for me, and has worked fine for like a decade or more.
LionEgo 1y ago
It depends on the game/application and what you are running and your distro may have enabled TearFree for you. I use Debian and it isn't enabled by default. If I was to play Dark Souls 3 and/or Elden ring on Linux without tearfree. There is significant screen tearing and the game feels very choppy when playing. To enable TearFree on Xorg. You typically make a new configuration file that sits in /etc/X11/xorg.conf.d/ and append to the X configuration https://wiki.archlinux.org/title/AMDGPU#Tear_free_rendering https://wiki.archlinux.org/title/AMDGPU#Tear_free_rendering There are downside to this, but I would only imagine they are problems on older GPUs. https://unix.stackexchange.com/questions/518362/whats-the-downside-to-tearfree-with-intel-graphics https://unix.stackexchange.com/questions/518362/whats-the-do... I've never noticed these downsides personally and everything seems to work great. I don't like Wayland. It still seems very buggy and I am running Debian Trixie and would prefer to keep using X11. But IME Wayland does have higher performance on older hardware it seems than X. My old laptop could barely play Youtube with X11 (it is the video itself not YouTube being a resource hog, I checked), Wayland performance is much better.
- simoncion 1y ago
  > (it is the video itself not YouTube being a resource hog, I checked) Did you check by downloading the video and playing it with a good standalone video player like mplayer, vlc, or mpv? If you didn't, then you didn't disentangle the web browser from the video playback.
  - LionEgo 1y ago
    I've spent a lot of time in my career working on weird rendering issues on websites/devices. Believe me when I said "I checked", I know WTF I am talking about. The only thing that was different was Wayland vs X11. Same browser, same browser settings, same OS and same plugins.
    - simoncion 1y ago
      > Same browser, same browser settings, same OS and same plugins. Neat. Did you test outside of the browser? Based on your report, it sounds like you didn't. As you must know, the renderers in web browsers are very, very complex. I suggest you test with a standalone video player before you go blaming the underlying windowing system for performance issues.
const_cast 1y ago
> But can I ssh to my remote server and run emacs or another program completely transparently yet with Wayland? Nope. I do that with X11 continuously The problem is this usecase sucks major ass on X and has for a decade at least. It worked meh at one point, but as modern applications became more complex and X exploded in complexity it no longer makes any sense. X is an unbelievably chatty protocol. Believe it or not, it's primarily meant to be run on a local socket, which is almost certainly memory mapped. Running it over the network has incredible latency, terrible lag spikes, and your windows will just kill themselves somewhat randomly. There are newer remote desktop protocols which are literally just better.

by rwmj 1y ago

toast0 1y ago

I've seen video tearing on X. Usually it doesn't happen, often it's hard to notice anyway; and when it did happen and was annoying, I just was missing some setting or other. No big deal.

ndiddy 1y ago

> But can I ssh to my remote server and run emacs or another program completely transparently yet with Wayland? Nope. Yes, you can! Waypipe came out 6 years ago. Its express purpose is to make a Wayland equivalent to ssh -X. https://gitlab.freedesktop.org/mstoeckl/waypipe/ https://gitlab.freedesktop.org/mstoeckl/waypipe/

aragilar 1y ago
Except: 1. It's Wayland-to-Wayland (which means you're much more limited to where it can run than X-to-X, where's the MacOS or Windows or BSD Wayland build?). 2. It's not integrated with ssh (X forwarding is part of the protocol). 3. You need it on both the client and the server, so you need to work out how to get it onto the server.

nullc 1y ago

If someone shows it to you, you'll recognize it. It's when one frame shows part of the prior frame and part of the next. It's most visible in moderate speed horizontal pans as an interruption in vertical lines in the picture. It's nice to not have tearing. But IMO the functionality loss vs X11 isn't worth it for anything but a dedicated media playback/editing device.

simoncion 1y ago
> It's nice to not have tearing. If you're running AMD hardware, try enabling the TearFree option. [0] I've been using this for years and years and years and it works fine. [0] See this for a config file you could plop into place: <https://news.ycombinator.com/item?id=44375247 https://news.ycombinator.com/item?id=44375247>

kiwijamo 1y ago

I used to see it all the time on X11. I'd see it on YouTube/Firefox. I'd see it on VLC. I'd see it on MPV. Any video player, playing any fast paced video you'll see X11 struggle to keep up with drawing full frames that it'd just give up and draw half of one frame and another half of another frame and call it a day. The Intel driver luckily had an xorg.conf setting I could add to make this less of an issue -- I guess it'd turn on some internal Intel driver logic to skip frames or something else if it wasn't able to draw the entire video frame in time for display. However as soon as Debian made Wayland the default this issue 100% disappared and I no longer needed to edit a conf file to make my display work correctly. This is hands-down the singular reason I love Wayland. It just works without any faffing around as Windows, MacOS, etc has done since the mid 1990's. Wayland has achieved more in 5 years than X11 has done in the last 25 years.

kelnos 1y ago
So basically what you are saying is that they could have changed a default in a config file somewhere, 5 minutes of work, but instead they decided to spend hundreds (thousands?) of person-years building something new from scratch? And that's a good thing? Oof.
- kiwijamo 1y ago
  I assume there's a reason Intel didn't make that particular setting the default in their x11 drivers. While it certainly fixed the screen tearing issue, I presume there was some tradeoff which made some other feature worse off. Wayland however I assume is already built so it doesn't need the driver to implement some workaround to fix it, it's already designed to correctly handle video output by ensuring only the full frame is rendered every single frame.
  - LionEgo 1y ago
    > To summarise, the downsides are that it requires more memory, and that it reduces throughput and adds latency (except when there’s already a compositor or a vblank-synced fullscreen display). https://unix.stackexchange.com/questions/518362/whats-the-downside-to-tearfree-with-intel-graphics https://unix.stackexchange.com/questions/518362/whats-the-do... I think the extra requirements aren't a problem on modern cards. However on lower end devices e.g. the older intel iGPUs, I could see this becoming an issue.

ginko 1y ago

Worst was with the discussion about Wayland having extra latency on mouse pointer movements. The explanation there was that X11 used HW pointer device that got updated as soon as there was a change but that might lead to gasp occasional pointer tearing. So better add a couple ms of latency to everything in Wayland and sample the mouse pointer position once per frame. FWIW, I do see screen tearing on my X11 multi-monitor setup. I just don't care.

simoncion 1y ago
> FWIW, I do see screen tearing on my X11 multi-monitor setup. I just don't care. If you ever get really bored one day, and you have nothing else to do, and you're using AMD/ATi hardware, try enabling the TearFree option for your video card driver. Something like Section "Device" Identifier "AMD" Driver "amdgpu" Option "TearFree" "on" EndSection in a new .conf file in '/etc/X11/xorg.conf.d' and a restart of your display server(s) should do the trick. It works fine for me, and has worked fine for like a decade or more.

LionEgo 1y ago

It depends on the game/application and what you are running and your distro may have enabled TearFree for you. I use Debian and it isn't enabled by default. If I was to play Dark Souls 3 and/or Elden ring on Linux without tearfree. There is significant screen tearing and the game feels very choppy when playing. To enable TearFree on Xorg. You typically make a new configuration file that sits in /etc/X11/xorg.conf.d/ and append to the X configuration https://wiki.archlinux.org/title/AMDGPU#Tear_free_rendering https://wiki.archlinux.org/title/AMDGPU#Tear_free_rendering There are downside to this, but I would only imagine they are problems on older GPUs. https://unix.stackexchange.com/questions/518362/whats-the-downside-to-tearfree-with-intel-graphics https://unix.stackexchange.com/questions/518362/whats-the-do... I've never noticed these downsides personally and everything seems to work great. I don't like Wayland. It still seems very buggy and I am running Debian Trixie and would prefer to keep using X11. But IME Wayland does have higher performance on older hardware it seems than X. My old laptop could barely play Youtube with X11 (it is the video itself not YouTube being a resource hog, I checked), Wayland performance is much better.

simoncion 1y ago
> (it is the video itself not YouTube being a resource hog, I checked) Did you check by downloading the video and playing it with a good standalone video player like mplayer, vlc, or mpv? If you didn't, then you didn't disentangle the web browser from the video playback.
- LionEgo 1y ago
  I've spent a lot of time in my career working on weird rendering issues on websites/devices. Believe me when I said "I checked", I know WTF I am talking about. The only thing that was different was Wayland vs X11. Same browser, same browser settings, same OS and same plugins.
  - simoncion 1y ago
    > Same browser, same browser settings, same OS and same plugins. Neat. Did you test outside of the browser? Based on your report, it sounds like you didn't. As you must know, the renderers in web browsers are very, very complex. I suggest you test with a standalone video player before you go blaming the underlying windowing system for performance issues.

const_cast 1y ago

> But can I ssh to my remote server and run emacs or another program completely transparently yet with Wayland? Nope. I do that with X11 continuously The problem is this usecase sucks major ass on X and has for a decade at least. It worked meh at one point, but as modern applications became more complex and X exploded in complexity it no longer makes any sense. X is an unbelievably chatty protocol. Believe it or not, it's primarily meant to be run on a local socket, which is almost certainly memory mapped. Running it over the network has incredible latency, terrible lag spikes, and your windows will just kill themselves somewhat randomly. There are newer remote desktop protocols which are literally just better.