Display update problems with Xorg extension

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martin f krafft

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Aug 20, 2021, 10:26:43 PM8/20/21
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Hello there,

I've just configured two Debian laptops to use the X.org extension. X.org server is 1.20.11-1, and the TigerVNC module version is 1.11.0, though it announces itself as 1.0.0 in the log:

[  1285.129] (II) Module vnc: vendor="TigerVNC Project"  
[  1285.129]    compiled for 1.20.10, module version = 1.0.0  
[  1285.129]    Module class: X.Org Server Extension  
[  1285.129]    ABI class: X.Org Server Extension, version 10.0  

Both laptops are running Xfce 4.16 from Debian bullseye.

On one laptop, it works just fine (resolution 1600×900), but on the other laptop (1920×1080), the VNC display is completely screwed up. Check it out here, when I try to move a window: https://stuff.madduck.net/scratch/tigervnc-weirdness.gif
Note that this persists across different VNC clients, so I conclude it's a server-side problem.

Now, if I change the resolution to 1600×900 on that laptop, it works fine, and so at first I was thinking that TigerVNC just cannot handle the big resolution, but I noticed that LightDM displays just fine at 1920×1080, and so does a session with the AwesomeWM window manager.

Has anyone seen this before? What does Xfce on this laptop do to make TigerVNC not be able to properly work?

Thanks,

--

@martinkrafft | https://matrix.to/#/#madduck:madduck.net


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have all the cold blood of an experienced attorney."

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Pierre Ossman

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Aug 26, 2021, 8:48:22 AM8/26/21
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On 21/08/2021 04:26, 'martin f krafft' via TigerVNC User
Discussion/Support wrote:
>
> Has anyone seen this before? What does Xfce on this laptop do to make
> TigerVNC not be able to properly work?
>

My first guess would be this bug:

https://github.com/TigerVNC/tigervnc/issues/1218

Could you check if glamor seems to be active on this device?

Regards
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Pierre Ossman Software Development
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Phone: +46-13-214600

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?

martin f krafft

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Aug 26, 2021, 6:32:00 PM8/26/21
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Thanks for your response, Pierre!

Could you check if glamor seems to be active on this device?

Yes, the module is being loaded during Xorg start. I've tried to Disable it, but Load overrides Disable, and something explicitly loads it. So I renamed the module file itself, and consequently, glamoregl fails to load, and — tadaaa — the problem is gone.

Well spotted!

Now I am wondering what the best solution is. What do I need Glamor for?

there is no place like ~


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Pierre Ossman

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Aug 27, 2021, 9:42:31 AM8/27/21
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On 27/08/2021 00:31, 'martin f krafft' via TigerVNC User
Discussion/Support wrote:
> Thanks for your response, Pierre!
>
>> Could you check if glamor seems to be active on this device?
>
> Yes, the module is being loaded during Xorg start. I've tried to
> `Disable` it, but `Load` overrides `Disable`, and something explicitly
> loads it. So I renamed the module file itself, and consequently,
> `glamoregl` fails to load, and — tadaaa — the problem is gone.
>
> Well spotted!
>
> Now I am wondering what the best solution is. What do I need Glamor for?
>

It handles all your hardware acceleration, so it's something you really
want. Unfortunately we can't fix it in our end, and we aren't aware of
any workaround. So this needs to be reported to your distribution so
someone has a look at fixing the glamor code.

martin f krafft

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Aug 27, 2021, 4:57:57 PM8/27/21
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Regarding the following, written by "Pierre Ossman" on 2021-08-27 at 15:42 Uhr +0200:

It handles all your hardware acceleration, so it's something you really want. Unfortunately we can't fix it in our end, and we aren't aware of any workaround. So this needs to be reported to your distribution so someone has a look at fixing the glamor code.

As far as I understand, the bug is already reported upstream, so there's little point in filing a bug against Debian stable, which has just been released.

Thanks for your help!

"william blake, you're a dead man!"

-- nobody


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Pierre Ossman

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Sep 2, 2021, 9:57:18 AM9/2/21
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On 27/08/2021 22:57, 'martin f krafft' via TigerVNC User
Discussion/Support wrote:
>
> As far as I understand, the bug is already reported upstream, so there's
> little point in filing a bug against Debian stable, which has just been
> released.
>
> Thanks for your help!
>

Sometimes issues need to be raised in multiple places. They won't
prioritise a fix if they don't know that users are affected by it.
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