switching linux kernels

[Graham Stoney]

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

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/