Re: dma_alloc_coherent issue with tg3 in x86_64 build

[Chris Wright <chrisw@osdl.org>]

* Ian Pratt (m+Ian.Pratt@cl.cam.ac.uk) wrote:
> 
> > During boot of dom0, I get the following.  Box is remote, so 
> > I'm now waiting for proxy power button pusher ;-)  tg3 init 
> > fails doing dma_alloc_coherent (I assume this is from 
> > tg3_init_one -> tg3_test_dma -> pci_alloc_consistent -> 
> > dma_alloc_coherent).  Looks like an issue with the amount of 
> > memory in dom0.  Is this known?
> 
> Is this with a debug=y build of Xen? I can see how that might provoke
> the situation more than other builds.

Yes, it is.

> Do you know how large a contiguous chunk the tg3 needs? 

I believe that one was just 2 pages.

> I guess we could hold onto a few large chunks before making the dom0
> memory allocation.
> 
> Alternatively, if we get a failure, we should round up to the next power
> of two and then balloon out that much memory. Repeat until success...

I guess that'd be quick that early in boot.

thanks,
-chris