From: "Kendall Bennett" <KendallB@scitechsoft.com>
To: linuxppc-dev@ozlabs.org
Subject: Write Combining for PowerPC?
Date: Fri, 10 Dec 2004 13:23:06 -0800 [thread overview]
Message-ID: <41B9A33A.26557.5DDD7EC8@localhost> (raw)
Hi Guys,
We are working on some PowerPC machines and noticed that the boxes don't
appear to support the equivalent of Write Combining that we get on x86
boxes. Copies to Video Memory on our Motorola Sandpoint box run about
10Mb/s, which is terribly, terribly slow!
Does anyone know if it is possible to do something similar to Write
Combining for the PowerPC architecture, to speed up CPU access to the
linear framebuffer? Part of the problem is that for video overlay support
(not motion compensation) you have to dump the entire YUV frame into
video memory for the hardware overlay, and even on a 1GHz PPC box playing
an MPEG2 stream is not possible as X takes up over 80% of the CPU just to
copy the YUV data to video memory!
Obviously bus mastering will help solve this problem, but it would be
better if there was a way to enabling faster CPU access to the
framebuffer as well.
Regards,
---
Kendall Bennett
Chief Executive Officer
SciTech Software, Inc.
Phone: (530) 894 8400
http://www.scitechsoft.com
~ SciTech SNAP - The future of device driver technology! ~
next reply other threads:[~2004-12-10 22:02 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-12-10 21:23 Kendall Bennett [this message]
2004-12-17 21:16 ` Write Combining for PowerPC? Antonio Vargas
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