ubuntu-x-swat team mailing list archive

[Zorael <zorael@xxxxxxxxx>]

Public bug reported:

Binary package hint: xserver-xorg-input-synaptics

The cursor speed of a Synaptics pad depends on your screen size. Or
rather, "the speed value defines the scaling between touchpad
coordinates and screen coordinates." (man synaptics, line ~418). So
supposedly, even if you raise or lower your resolution, moving your
finger n millimetres across the pad surface should still make it move
the cursor n centimetres across your screen, regardless of whether the
screen's pixel resolution is at 800x600 or at 1600x1200.

Connecting an external monitor seems to count as adding screen
realestate, affecting the "effective screen speed" as much as raising
your resolution by that of the external monitor would. To put into a
concrete example: if your netbook screen is 1024x600, and you connect a
1600x1200 monitor, then the screen realestate becomes 2624x1200 if put
side-by-side, or 1600x1800 if put above the other. (Unsure of the
details of how the driver calculates this.)

The sensitivity that you get on your 1024x600 netbook screen, when the
Synaptics driver scales its speed to match your total 2624x1200
realestate, is much too high.

How to reproduce:
1) Acquire a netbook with a puny ~10" screen with 1024x600 native resolution (MSI Wind, et al)
2) Get a feel for the touchpad's cursor speed
3) Attach 1600x1200+ external monitor
4) Using xrandr, set the external monitor's output to be next to or above the laptop screen's output, as such;
   $ xrandr --output VGA1 --above LVDS1 --auto
5) Compare cursor speed to earlier speed
6) Try to perform simple to complex mouse tasks on your small screen and watch the cursor consistently overshoot

The speed is acceptable when maneuvering on the external monitor, but
very little physical pad movement is needed to totally pan over the
entirety of the small netbook screen.

Cursor speed should be screen-dependent, if that's even technically
possible. Alternatively, it should only take the "primary" screen
(output) into consideration when scaling pad movement speed to screen
cursor speed.

ProblemType: Bug
Architecture: i386
Date: Thu Feb 18 01:11:21 2010
DistroRelease: Ubuntu 10.04
DkmsStatus:
 ipheth, 1.0+git20100207, 2.6.32-12-generic, i686: installed 
 ipheth, 1.0+git20100207, 2.6.32-13-generic, i686: installed
InstallationMedia: Kubuntu 10.04 "Lucid Lynx" - Alpha i386 (20100201)
MachineType: MICRO-STAR INTERNATIONAL CO., LTD U-100
Package: xserver-xorg-input-synaptics 1.2.0-3ubuntu2
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-13-generic root=UUID=bfe2926e-f8bf-41dd-a237-690b609cafe6 ro quiet splash
ProcEnviron:
 LANGUAGE=
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.32-13.18-generic
RelatedPackageVersions:
 xserver-xorg 1:7.5+1ubuntu2
 libgl1-mesa-glx 7.7-0ubuntu8
 libdrm2 2.4.17-1ubuntu1
 xserver-xorg-video-intel 2:2.9.1-1ubuntu4
SourcePackage: xserver-xorg-input-synaptics
Uname: Linux 2.6.32-13-generic i686
dmi.bios.date: 10/06/2008
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 4.6.3
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: U-100
dmi.board.vendor: MICRO-STAR INTERNATIONAL CO., LTD
dmi.board.version: Ver.001
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: MICRO-STAR INTERNATIONAL CO., LTD
dmi.chassis.version: Ver.001
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr4.6.3:bd10/06/2008:svnMICRO-STARINTERNATIONALCO.,LTD:pnU-100:pvrVer.001:rvnMICRO-STARINTERNATIONALCO.,LTD:rnU-100:rvrVer.001:cvnMICRO-STARINTERNATIONALCO.,LTD:ct3:cvrVer.001:
dmi.product.name: U-100
dmi.product.version: Ver.001
dmi.sys.vendor: MICRO-STAR INTERNATIONAL CO., LTD
system:
 distro:             Ubuntu
 architecture:       i686kernel:             2.6.32-13-generic

** Affects: xserver-xorg-input-synaptics (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: apport-bug i386 lucid

-- 
Synaptics cursor speed is not screen-dependent - speed on small screen is too high after connecting big external monitor
https://bugs.launchpad.net/bugs/523558
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