Cache coherency question

Liu Dave-r63238 DaveLiu at
Mon Aug 28 13:17:32 EST 2006

> Ah.  This must be the problem.  I have a few PCI devices, and 
> on one of them it looked like snooping was working.  I just 
> assumed the other device was setup correctly.

Why one is looked like snooping was working, and the other device
not working?

> > Also, you can define the CONFIG_NOT_COHERENT_CACHE, then you are 
> > assuming The system has not hardware coherency. You need use the 
> > software to keep the cache coherency.
> > 
> I tried this, and got compiler errors.

What is the file got compiler errors? I notice that the

> I added some inline assembly dcbi/dcbf (invalidate/flush) 
> instructions to the particular code in question, and the 
> problems went away.  So definitely a cache problem.  As I 
> said above, defining CONFIG_NOT_COHERENT_CACHE causes 
> compiler errors, so I'm going to look into this more.  I 
> suppose whatever file implements the 
> include/linux/dma-mapping.h stuff isn't BSP specific, so its 
> probably just not being compiled in?  Will look into it.

Somebody said from maillist. The bridge MV64360 seems
having some issue about cache coherent. I don't know if it is really?


More information about the Linuxppc-embedded mailing list