svn commit: r290130 - head/sys/dev/ntb/ntb_hw

[John Baldwin]

On Thursday, October 29, 2015 04:16:28 AM Conrad E. Meyer wrote:
> Author: cem
> Date: Thu Oct 29 04:16:28 2015
> New Revision: 290130
> URL: https://svnweb.freebsd.org/changeset/base/290130
> 
> Log:
>   ntb: Do not attempt to set write-combining on MWs
>   
>   AMD64 pmap assumes ranges will be in the DMAP, which isn't necessarily
>   true for NTB memory windows (especially 64-bit BARs).
>   
>   Suggested by:	pmap_change_attr_locked -> kassert_panic
>   Sponsored by:	EMC / Isilon Storage Division

Hmm, pmap_mapdev_attr() does the right thing, but there isn't a good way to
call that directly (and still get a valid bus handle/tag).  I have on my todo
to add a bus_map_resource() that would let you allocate a bus handle/tag that
1) is a subset of a resource, and 2) specifies a memory attribute.  It would
allow you to do this sanely.

-- 
John Baldwin