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#1 2011-05-14 21:49:22

Deciare
Member
From: UTC -5:00
Registered: 2005-05-05
Posts: 78

Mouse pointer constrained by invisible boundaries after xrandr --scale

A couple of months ago, I learnt that it was possible to approximate a higher screen resolution than my netbook's native resolution by using xrandr. A command line like the following:

xrandr --output LVDS1 --scale 1.25x1.25

Would cause the whole screen to be scaled by 25%, artificially increasing my screen resolution to 1280x750 (up from 1024x600). It worked well at the time.

When I tried doing that again today, the screen looked fine, but I found that I couldn't move the mouse pointer beyond the original 1024x600 boundary. So the bottom quarter and right quarter of the screen were entirely inaccessible, as though the mouse pointer was bumping against an invisible barrier. Windows and menus and stuff could still draw there; it just couldn't be reached with the mouse pointer.

I tried the same command line on a different netbook running Ubuntu Lucid, and it works fine there. No issues with the mouse pointer. Both netbooks I tested with are the same model: Acer Aspire One A110L (AOA110-1302).

So what's happening here? What am I missing? I would appreciate any help.

Last edited by Deciare (2011-05-14 21:52:09)

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#2 2011-05-15 14:27:45

frony0
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From: London, United Kingdom
Registered: 2011-05-01
Posts: 43
Website

Re: Mouse pointer constrained by invisible boundaries after xrandr --scale

I'm not sure, but I think at one point I had the same problem it helped me to set the panning to the same value as the scaled resolution. As in

xrandr --output LVDS1 --scale 1.25x1.25 --panning 1280x750

Correct me if I'm wrong...


Make it idiot-proof, and someone will breed a better idiot.
-- Oliver Elphick

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#3 2011-05-15 15:37:34

Deciare
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From: UTC -5:00
Registered: 2005-05-05
Posts: 78

Re: Mouse pointer constrained by invisible boundaries after xrandr --scale

Thank you for the suggestion.

I tried that, along with just --panning without --scale. I'm only able to pan down and right by one pixel before the pointer gets stuck at the same invisible boundary...

Last edited by Deciare (2011-05-15 15:38:01)

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#4 2011-05-15 19:45:27

w33ky
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From: Germany
Registered: 2011-05-15
Posts: 3

Re: Mouse pointer constrained by invisible boundaries after xrandr --scale

I have the same problem with this invisible boundary.
... I hope this will be fixed soon.

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#5 2011-05-15 20:11:05

frony0
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From: London, United Kingdom
Registered: 2011-05-01
Posts: 43
Website

Re: Mouse pointer constrained by invisible boundaries after xrandr --scale

Ok, sorry, another suggestion. When you run xrandr with no parameters, is the resolution after "current" in the first line your original resolution? If not, try

xrandr --output LVDS1 --fb 1280x750

Though that should be automatic, I think. Beyond that, I've no idea tongue


Make it idiot-proof, and someone will breed a better idiot.
-- Oliver Elphick

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#6 2011-05-15 20:21:47

Deciare
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From: UTC -5:00
Registered: 2005-05-05
Posts: 78

Re: Mouse pointer constrained by invisible boundaries after xrandr --scale

I'm sorry to say that --fb doesn't work either. ^^;

xrandr --fb 1280x750 --output LVDS1 --scale 1.25x1.25 --panning 1280x750+0+0/1280x750+0+0/64/64/64/64

The elaborate command above doesn't allow my pointer to escape the invisible wall.

xrandr output from the command above is as follows:

Screen 0: minimum 320 x 200, current 1280 x 750, maximum 4096 x 4096
LVDS1 connected 1280x750+0+0 (normal left inverted right x axis y axis) 195mm x 113mm panning 1280x750+0+0 tracking 1280x750+0+0 border 64/64/64/64
   1024x600       60.0*+
   800x600        60.3     56.2 
   640x480        59.9 
VGA1 disconnected (normal left inverted right x axis y axis)

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#7 2011-05-15 20:28:55

w33ky
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From: Germany
Registered: 2011-05-15
Posts: 3

Re: Mouse pointer constrained by invisible boundaries after xrandr --scale

My native resolution is 1024x600.
The resolution I want to reach by scaling is 1376x768.

When I scale up to 1376x768 and use --fb 1376x768 then there is no change, when I use --fb 1024x600 then I get a smaller image of my desktop with black borders on the right and in the bottom. The smaller image of my desktop seams to match the size of the invisible border the mouse pointer can't leave.

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#8 2011-05-15 22:51:54

NiyaFox
Member
Registered: 2011-05-15
Posts: 1

Re: Mouse pointer constrained by invisible boundaries after xrandr --scale

Okay, I tried this with the latest version of Ubuntu which is running X server 1.10.1, RandR 1.3 and xrandr 1.3.4 -- same versions as my Arch install.

xrandr --output LVDS1 --scale 1.25x1.25 there not only scales the display but also permits the cursor full access to the screen (ie: the bug is not present)

I wonder if this is helpful?

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#9 2011-05-16 06:08:59

w33ky
Member
From: Germany
Registered: 2011-05-15
Posts: 3

Re: Mouse pointer constrained by invisible boundaries after xrandr --scale

Does your pc also have an Intel gma grafics chip?
Maybe the problem is related to it.

I tried on an Asus eeepc 1000H with Intel gma 950.
https://bugs.archlinux.org/task/24274

Last edited by w33ky (2011-05-16 09:40:30)

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#10 2011-05-18 15:24:04

sublimepua
Member
Registered: 2011-02-02
Posts: 12

Re: Mouse pointer constrained by invisible boundaries after xrandr --scale

farewell guys. I've tried to fix this myself, but I am not that experienced. I've tried to live with it, but its painful and a little ridiculous. I'm subscribed to the bugtracker, but I will be leaving arch linux until this problem is fixed. I hope that it doesn't take too long. Now I've gotta choose between slackware, ubuntu, and gentoo. Gross.

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#11 2011-11-27 09:52:47

delcypher
Member
Registered: 2010-04-17
Posts: 42

Re: Mouse pointer constrained by invisible boundaries after xrandr --scale

This problem bit me today. I tried scaling and panning. Both are broken as the mouse can't move out of the original screen area

It appears to be an Xorg bug:

https://bugs.freedesktop.org/show_bug.cgi?id=39949

Some patches have been submitted but I don't see anyone upstream actually accepting the patch.

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#12 2011-11-28 04:55:28

Deciare
Member
From: UTC -5:00
Registered: 2005-05-05
Posts: 78

Re: Mouse pointer constrained by invisible boundaries after xrandr --scale

Ah, perfect! Reverting http://cgit.freedesktop.org/xorg/xserve … 44eb1a0a11 (referenced from https://bugs.freedesktop.org/show_bug.cgi?id=40063) is exactly the workaround I needed. Thank you for pointing out that bug report.

Last edited by Deciare (2011-11-28 04:55:48)

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#13 2012-01-31 11:08:05

josvanr
Member
Registered: 2011-03-15
Posts: 4

Re: Mouse pointer constrained by invisible boundaries after xrandr --scale

Hello, I'm trying to do this also but no succes until now. When I try to revert the patch I get something like 'detected previously unreverted patch' or somethig. Could you briefliy tell what you did; which files did you download and what did you do to revert the patch?

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#14 2012-01-31 20:02:33

Deciare
Member
From: UTC -5:00
Registered: 2005-05-05
Posts: 78

Re: Mouse pointer constrained by invisible boundaries after xrandr --scale

Since you are reverting the patch, you need to indicate that the patch should be reversed on the command line. So if you saved the patch from git as constrain-cursor-harder.patch, for instance, you would need to modify the PKGBUILD so that:

  • constrain-cursor-harder.patch is in the source array

  • The patch's md5sum is in the md5sums array

  • The patch command line specifies that it's a reverse patch (the -R is important):

    patch -RNp1 -i "${srcdir}/constrain-cursor-harder.patch"

Unfortunately, the patch from git no longer reverses cleanly against xorg-server 1.11.4.

I've made an updated version of the patch that should apply cleanly, without a need to be reversed, here: http://moe.isisview.org/patches/xorg-se … rder.patch

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#15 2012-01-31 20:06:52

karol
Archivist
Registered: 2009-05-06
Posts: 25,427

Re: Mouse pointer constrained by invisible boundaries after xrandr --scale

Should this go upstream?

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#16 2012-01-31 20:27:30

Deciare
Member
From: UTC -5:00
Registered: 2005-05-05
Posts: 78

Re: Mouse pointer constrained by invisible boundaries after xrandr --scale

Can do. Attached patch to upstream bug report: https://bugs.freedesktop.org/show_bug.cgi?id=39949

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#17 2012-07-13 19:48:27

igge
Member
Registered: 2012-04-21
Posts: 2

Re: Mouse pointer constrained by invisible boundaries after xrandr --scale

Does anyone now if there is a solution to this problem?
Is still can't get it to work. I want my netbook to use 1024*768 and the
screen resolution is at that but the mouse pointer is still constrained
by invisible boundaries.

//Igge

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#18 2012-07-13 19:59:38

Gusar
Member
Registered: 2009-08-25
Posts: 3,447

Re: Mouse pointer constrained by invisible boundaries after xrandr --scale

This seems to work if you go by comments: https://bugs.freedesktop.org/show_bug.cgi?id=39949#c20

Though I also recall AaronP of Nvidia posting some patch not long ago, but I'm not sure. I'll do a search, see what I can find. Edit: Hmm, for now all I can find is this: http://article.gmane.org/gmane.comp.fre … 138/match= <- quite useful in that you don't have to calculate scale factors yourself. But I have some vague memory he also posted another patch too. Seems not, though. There is another randr patch he posted, but it's unrelated to this issue.

Last edited by Gusar (2012-07-13 20:14:42)

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#19 2012-10-17 23:33:22

karol
Archivist
Registered: 2009-05-06
Posts: 25,427

Re: Mouse pointer constrained by invisible boundaries after xrandr --scale

This seems to be fixed now https://bugs.archlinux.org/task/24274
I've tried it and it works for me.

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