Software and hardware annotations 2009 July

This document contains only my personal opinions and calls of judgement, and where any comment is made as to the quality of anybody's work, the comment is an opinion, in my judgement.

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090714 Tue Many difficulties with CentOS5 and dual displays

As part of an upgrade or downgrade from Fedora 8 to CentOS 5 on my laptop there has been the need to get internal and external monitors work again.

The issue is that Fedora 8 had an X server and tools supporting RANDR which allows not just pretend-resizing the current X screen, but also adding new outputs to it, but CentOS 5 only supports RANDR version 1.1, which only allows resizing.

Therefore with RANDR 1.1 one must configure the X server statically with the number of monitors it must support at any one time, and this can mean one of three setups:

• A single X display with two X screens managed using XINERAMA (or equivalent proprietary alternatives like TwinView) as if joined.
• A single X display with two X screens kept separate, with a single or two window managers.
• Two distinct X displays, each with a single X screen or two, on separate virtual consoles.