Re: kern/50038: udl (DisplayLink GX-DVI_U2B) alignment fault on earmv6hf NETWALKER

[Nick Hudson <skrll%netbsd.org@localhost>]

The following reply was made to PR kern/50038; it has been noted by GNATS.

From: Nick Hudson <skrll%netbsd.org@localhost>
To: gnats-bugs%NetBSD.org@localhost, kern-bug-people%netbsd.org@localhost,
 gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost, mochid%netside.co.jp@localhost
Cc: 
Subject: Re: kern/50038: udl (DisplayLink GX-DVI_U2B) alignment fault on
 earmv6hf NETWALKER
Date: Tue, 15 Nov 2016 10:33:11 +0000

 On 11/14/16 20:30, MOCHIDA Shuji wrote:
 > The following reply was made to PR kern/50038; it has been noted by GNATS.
 >
 > From: MOCHIDA Shuji <mochid%netside.co.jp@localhost>
 > To: martin%duskware.de@localhost
 > Cc: skrll%netbsd.org@localhost, gnats-bugs%NetBSD.org@localhost, kern-bug-people%netbsd.org@localhost,
 >   gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost, mochid%netside.co.jp@localhost
 > Subject: Re: kern/50038: udl (DisplayLink GX-DVI_U2B) alignment fault on
 >   earmv6hf NETWALKER
 > Date: Tue, 15 Nov 2016 03:31:56 +0900 (JST)
 >
 >   Easy workaround below. May something related to alignment.
 >   In these functions, (curcpu()->ci_ctrl & CPU_CONTROL_AFLT_ENABLE) is zero.
 >   This should not be zero?
 >   
 
 We should be running with SCTLR.A =0 and SCTLR.U = 1, i.e.
 CPU_CONTROL_AFLT_ENABLE unset and CPU_CONTROL_UNAL_ENABLE set, but
 I think the usb transfer buffer is being marked as device/strongly 
 ordered memory and
 we get an unaligned access fault because of this.
 
 Nick