Thread (7 messages) 7 messages, 4 authors, 2000-10-06

Re: switching linux kernels

From: Graham Stoney <hidden>
Date: 2000-09-27 00:40:21

Julia Elbert writes:
In 2.2.14, I need to have the Copy-Back Data Cache option off for my drivers
to work with video, same as in 2.2.13, or I else I get corrupted video data.
Turning off copy-back has a global performance hit, so it's a pretty nasty
workaround for cache coherency bugs in a single driver.  It's OK when it gets
you going in a pinch, but as you've found, these bugs keep coming back to bite
every time you upgrade to a more aggressive caching regimen.  Also, perhaps
your driver isn't doing I/O barrier stuff properly; does it use insx/outsx &
friends from asm/io.h, or does it dereference pointers directly, forgetting
the eieio's?

Regards,
Graham
--
Graham Stoney
Principal Hardware/Software Engineer
Canon Information Systems Research Australia
Ph: +61 2 9805 2909  Fax: +61 2 9805 2929

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