Date: Fri, 3 Nov 2000 05:59:38 -0500 (EST) From: cgull@owl.org To: FreeBSD-gnats-submit@freebsd.org Cc: nsouch@freebsd.org, nicolas.souchu@prism.uvsq.fr, dfr@freebsd.org Subject: i386/22568: ppc panic with drq = 0 Message-ID: <200011031059.eA3AxcK00563@n.owl.org>
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>Number: 22568
>Category: i386
>Synopsis: ppc0 panics on DMA with drq set to 0
>Confidential: no
>Severity: serious
>Priority: high
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri Nov 03 03:00:02 PST 2000
>Closed-Date:
>Last-Modified:
>Originator: john hood
>Release: FreeBSD 4.1-20001028-STABLE i386
>Organization:
>Environment:
Asus A7V motherboard with super i/o's parallel port configured to port
0x378, irq 7, dma 3. kernel config derived from GENERIC; ppb and lpt
configuration identical to GENERIC.
>Description:
The ppc driver panics when requested to use DMA, when it is configured
to use DMA channel 0.
>How-To-Repeat:
boot kernel.GENERIC
lptcontrol -e
dd if=/dev/zero of=/dev/lpt0 bs=1024 count=1
panic: isa_dmastart: bad bounce buffer
boot kernel.GENERIC -c; drq ppc0 3
lptcontrol -e
dd if=/dev/zero of=/dev/lpt0 bs=1024 count=1
no panic.
>Fix:
Make ppc.c test ppc->ppc_dmachan consistently. I think drq 0 means
'unconfigured', so I did that.
A quick grovel through cvsweb shows the bug's existed since DMA
support was added.
--- ppc.c Fri Nov 3 05:06:31 2000
+++ /usr/src/sys/isa/ppc.c Sat Jul 22 05:09:36 2000
@@ -1657,7 +1657,7 @@
*/
if ((ppc->ppc_avm & PPB_ECP) && (ppc->ppc_registered)) {
- if (ppc->ppc_dmachan > 0) {
+ if (ppc->ppc_dmachan >= 0) {
/* byte mode, no intr, no DMA, dir=0, flush fifo
*/
>Release-Note:
>Audit-Trail:
>Unformatted:
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