[Novalug] Fedora 12 video question
Bryan J Smith
b.j.smith at ieee.org
Wed Oct 21 11:56:34 EDT 2009
Yes, overlays often have issues with spanned framebuffers.
The overlay often only works on the first framebuffer,
although it may not work on either, depending on implementation.
Are you using Xinerama? Or is the X driver doing the spanning?
In a nutshell, anytime you use a hardware feature - overlay
buffers (motion video), z-buffer (3D), etc..., it's not going work
over Xinerama, possibly only one display or neither. You must
use an X driver that still supports these features when spanned
across multiple screens.
Most X drivers use a single framebuffer for multiple screens
to solve this issue, although it introduces other issues, because
X doesn't know about the individual screens like it would with
Xinerama. Fortunately FreeDesktop standards have defined many
settings/APIs so even single framebuffer X drivers can correctly
communicate where individual displays start and end.
Unless I'm using a nVidia card, I don't span screens and expect
overlay support. For my T60, I mirror screens instead of
spanning so they are the same framebuffer.
Bryan J Smith - mailto:b.j.smith at ieee.org
Sent via BlackBerry from T-Mobile
From: greg pryzby <greg at pryzby.org>
Date: Wed, 21 Oct 2009 11:17:05
To: Novalug<novalug at calypso2.tux.org>
Subject: [Novalug] Fedora 12 video question
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