Cursor lagging with Linux KMS

Questions about Wine on Linux
Locked
Gullible Jones
Level 1
Level 1
Posts: 6
Joined: Sat Mar 06, 2010 4:14 pm

Cursor lagging with Linux KMS

Post by Gullible Jones » Sat Sep 11, 2010 9:05 am

A minor bug I've noticed: when kernel modesetting is enabled (as it is by default on most current Linux distributions), the mouse cursor lags for a few seconds when starting an application in Wine, or when a Wine'd application is doing some heavy activity.

The former is not really worth mentioning, but the latter actually causes problems in a few fullscreen games I've tried, since the cursor is freezing fairly constantly at certain times, hampering or preventing input.

Neither issue occurs with KMS disabled, assuming a distro on which KMS can be disabled. Both occur with all versions of Wine I've tried, from 1.0 to 1.3.

There are no console messages when the cursor lags.

Can anyone tell me what might be going on?

Gullible Jones
Level 1
Level 1
Posts: 6
Joined: Sat Mar 06, 2010 4:14 pm

Post by Gullible Jones » Sat Oct 29, 2011 10:44 am

Found the problem. It's polling by drm_kms_helper, as detailed here:

http://souriguha.wordpress.com/2011/03/ ... 2-35-2-36/

Putting "N" or "0" in /sys/modules/drm_kms_helper/parameters/poll, or booting with the "drm_kms_helper.poll=0" kernel parameter, fixes the issue (and a few others, e.g. kworker threads consuming excessive CPU time).

KMS polling seems to be related to autodetecting and configuring new display devices, so there may be issues with this fix if you have to use a projector or other hotpluggable display device. Not sure what those issues would be though.

Sorry if resurrecting a thread like this is frowned upon BTW...

Locked