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

[Julian Bourne <julian.bourne%gmail.com@localhost>]

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

From: Julian Bourne <julian.bourne%gmail.com@localhost>
To: gnats-bugs%netbsd.org@localhost, 
port-amd64-maintainer%netbsd.org@localhost, 
        gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost, 
julian.bourne%gmail.com@localhost
Cc: 
Subject: Re: port-amd64/42980: satalink DMA fails under amd64
Date: Thu, 18 Mar 2010 14:27:42 -0400

 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
 
 See trace I added to the code from my kernel logs:
 
 ../../../../arch/xen/x86/xen_bus_dma.c:259
   uvm_pglistalloc failed error=22, size=65536,
   alignment=4096, boundary=8192.
 satalink0:0: unable to create xfer table DMA map
   for drive 0, error=22
 wd0(satalink0:0:0): using PIO mode 4
 
 Hope that helps.
 
 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.