Re: kern/39093: usb doesn't work anymore on IBM T43p

[Kurt Schreiner <ks%ub.uni-mainz.de@localhost>]

The following reply was made to PR kern/39093; it has been noted by GNATS.

From: Kurt Schreiner <ks%ub.uni-mainz.de@localhost>
To: Manuel Bouyer <bouyer%antioche.eu.org@localhost>
Cc: "gnats-bugs%NetBSD.org@localhost" <gnats-bugs%NetBSD.org@localhost>,
   "kern-bug-people%NetBSD.org@localhost" 
<kern-bug-people%NetBSD.org@localhost>,
   "gnats-admin%NetBSD.org@localhost" <gnats-admin%NetBSD.org@localhost>,
   "netbsd-bugs%NetBSD.org@localhost" <netbsd-bugs%NetBSD.org@localhost>
Subject: Re: kern/39093: usb doesn't work anymore on IBM T43p
Date: Mon, 7 Jul 2008 13:33:31 +0200

 On Mon, Jul 07, 2008 at 12:59:09PM +0200, Manuel Bouyer wrote:
 > On Mon, Jul 07, 2008 at 10:36:35AM +0200, Kurt Schreiner wrote:
 > > On Sun, Jul 06, 2008 at 09:31:32PM +0200, Manuel Bouyer wrote:
 > > > On Fri, Jul 04, 2008 at 09:42:54PM +0200, Kurt Schreiner wrote:
 > > > > > Do you mean is started failing on Jun 27, or that it worked on Jun 
 > > > > > 27 and
 > > > > > started failing later ? I commited some changes to the USB drivers 
 > > > > > on Jun 28.
 > > > > First failure is from Jun 27. Here's the relevant excerpt from 
 > > > > /var/log/messages
 > [...]
 > > the problem. I've found a very old kernel from May, 4 which booted fine
 > [...]
 > OK, so it's definitively not related to my changes.
 Yep!
 
 > > [...]
 > > /var/log/messages.9.gz:Jun  7 21:40:17 ipaddi /netbsd: ath0: hardware 
 > > error; resetting
 > 
 > I don't know what these "hardware error" really means.
 Hm, digging for "hardware error" in ath.c brings up the following:
 
         if (status & HAL_INT_FATAL) {
                 /*
                  * Fatal errors are unrecoverable.  Typically
                  * these are caused by DMA errors.  Unfortunately
                  * the exact reason is not (presently) returned
                  * by the hal.  
                  */
 
 ...not giving much hints where to look for the real cause of this...
 
 > The cause of the UHCI errors is probably because the UHCI DMA descriptors
 > are invalid (or the controller thinks so). This could be because something
 > else is writing to memory and corrupts the UHCI DMA memory,
 > or because the some other device, or a chipset bug, cause data corruption
 > on the PCI bus when the UHCI controllers are doing their DMA reads.
 Hm, so everything points to problems w/ DMA... Time to go for the screwdriver
 and take things apart. The problem is hardware releated, I think.
 
 Very much thanks for your help!
 Kurt
 
 ps.: Can you close the PR please? I think it's not needed anymore...