Re: port-i386/38935: x86 bus_dmamap_sync() should use memory barrier

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

The following reply was made to PR port-i386/38935; it has been noted by GNATS.

From: Manuel Bouyer <bouyer%antioche.eu.org@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: port-i386-maintainer%NetBSD.org@localhost, gnats-admin%NetBSD.org@localhost,
        netbsd-bugs%NetBSD.org@localhost
Subject: Re: port-i386/38935: x86 bus_dmamap_sync() should use memory barrier
Date: Wed, 11 Jun 2008 00:08:51 +0200

 On Tue, Jun 10, 2008 at 09:30:02PM +0000, Andrew Doran wrote:
 > The following reply was made to PR port-i386/38935; it has been noted by 
 > GNATS.
 > 
 > From: Andrew Doran <ad%netbsd.org@localhost>
 > To: gnats-bugs%netbsd.org@localhost
 > Cc: 
 > Subject: Re: port-i386/38935: x86 bus_dmamap_sync() should use memory barrier
 > Date: Tue, 10 Jun 2008 22:25:12 +0100
 > 
 >  On Tue, Jun 10, 2008 at 09:20:02PM +0000, Andrew Doran wrote:
 >  
 >  >  I think x86_lfence() without any if() would be enough. Does it solve the
 >  >  problem for you?
 >  
 >  Bah, that will always evaluate to the equivalent of x86_mfence(). For this,
 
 What would always evaluate to x86_mfence ? x86_lfence(), or my code ?
 
 >  membar_consumer() would a be better test since it will be patched to 
 > 'lfence'
 >  during boot.
 
 where is it defined ? I'd like to know what it would look like on
 xen (xen doesn't use x86/patch.c for now).
 
 -- 
 Manuel Bouyer <bouyer%antioche.eu.org@localhost>
      NetBSD: 26 ans d'experience feront toujours la difference
 --