Re: port-amd64/42980: satalink DMA fails under amd64

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

The following reply was made to PR port-amd64/42980; it has been noted by GNATS.

From: Manuel Bouyer <bouyer%antioche.eu.org@localhost>
To: Julian Bourne <julian.bourne%gmail.com@localhost>
Cc: gnats-bugs%NetBSD.org@localhost, port-amd64-maintainer%NetBSD.org@localhost,
        gnats-admin%NetBSD.org@localhost, netbsd-bugs%NetBSD.org@localhost
Subject: Re: port-amd64/42980: satalink DMA fails under amd64
Date: Thu, 18 Mar 2010 20:15:24 +0100

 On Thu, Mar 18, 2010 at 02:27:42PM -0400, Julian Bourne wrote:
 > OK, I verified several things with the 5.0.2 kernel:
 > 
 > (1) amd64 GENERIC (non xen) suffers as well
 > (2) amd64 XEN_DOM0 suffers with or without Manuel's patch
 > (3) uvm_pglistalloc has the boundary >= size check as well
 
 OK; if uvm_pglistalloc had this check too, my patch won't help.
 I'll see how this can be fixed. uvm(9) doesn't say that
 uvm_pglistalloc() should not be called with a boundary smaller than
 size. Maybe it needs to be fixed too
 
 > 
 > If I can throw in 2c, I think the problem is that the bouncebuf
 > create call should be using the max segment size from the sc
 > structure, not MAXPHYS, but I admit, I'm way out of my depth.
 
 It would then need to create the segment list by itself, where
 we already have code to handle this.
 
 -- 
 Manuel Bouyer <bouyer%antioche.eu.org@localhost>
      NetBSD: 26 ans d'experience feront toujours la difference
 --