Re: Au1500 hardware cache coherency

[Ralf Baechle <ralf@linux-mips.org>]

On Mon, Mar 31, 2003 at 10:35:14AM -0800, Pete Popov wrote:

> > So before spending more time on debugging this, and creating patches
> > for using HW coherency, I wanted to hear your input - maybe there are
> > known problems in the Au1500 coherency implementation?
> 
> Looks like Eric already replied to your questions.
> 
> Patches to get the code to compile with NONCOHERENT_IO turned off would
> be good, even if you don't want to do that yet. 
> 
> FYI, in the latest kernel I'm getting a panic when doing a very large
> 'cp -a' from nfs to ata100 disk (don't know if the disk itself matters)
> (Pb1500 and Db1500).  The same test passes with a 2.4.18 kernel, so it
> seems like it's not a hardware issue, unless the 2.4.18 kernel is just
> getting lucky.  I'll be gone till 4/20 so I won't have time to debug it
> until after I get back.

Not that this is Linux 2.4.21-pre4 which did replace essentially the
entire IDE code due to major problems with the old IDE core.  The problems
were huge - large enough to warrant the rewrite of such a large subsystem
in a stable series of kernels and certainly the dust hasn't fully settled
yet.

  Ralf