Call for testing and review, busdma changes

[Ian Lepore]

On Sun, 2012-12-30 at 11:23 -0700, Scott Long wrote:
> On Dec 30, 2012, at 11:21 AM, Ian Lepore <freebsd at damnhippie.dyndns.org> wrote:
> 
> > On Mon, 2012-12-24 at 22:13 -0500, Scott Long wrote:
> >>>>> 
> >>>>> Still unresolved is what to do about the remaining cases -- attempts to
> >>>>> do dma in arbitrary buffers not obtained from bus_dmamem_alloc() which
> >>>>> are not aligned and padded appropriately.  There was some discussion a
> >>>>> while back, but no clear resolution.  I decided not to get bogged down
> >>>>> by that fact and to fix the mbuf and allocated-buffer situations that we
> >>>>> know how to deal with for now.
> >>>> 
> >> 
> >> Why would these allocations not be handled as normal dynamic buffers
> >> would with bus_dmamap_load()?
> >> 
> >> Scott
> > 
> > That's my point -- for "normal dynamic buffers" (that is, they weren't
> > obtained from bus_dmamem_alloc() and they aren't mbufs) which can have
> > arbitrary alignment and padding in relation to cache line boundaries --
> > we don't handle them correctly now unless they're accidentally already
> > aligned and sized to the right boundaries.  What's unresolved is how to
> > handle them correctly if they're not aligned/padded, that is, what to do
> > about them that avoids needing a partial cacheline flush at sync time.
> > 
> 
> Alignment is already handled.
> 
> Scott
> 

No it's not.

-- Ian