Date: Fri, 3 Sep 1999 09:00:15 +0100 (BST) From: Doug Rabson <dfr@nlsystems.com> To: Luoqi Chen <luoqi@watermarkgroup.com> Cc: arthur@tucows.com, freebsd-current@FreeBSD.ORG, nick.hibma@jrc.it Subject: Re: Problems with the sound card. Message-ID: <Pine.BSF.4.10.9909030900030.2081-100000@salmon.nlsystems.com> In-Reply-To: <199909030024.UAA02922@lor.watermarkgroup.com>
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On Thu, 2 Sep 1999, Luoqi Chen wrote:
> > That's exactly what I have. This is just so weird. I am now reading the
> > debug register chapter of intel's manual, it is virtually impossible to
> > pinpoint the location by single-stepping through the code...
> >
> The debug register trick worked, and the discovery was quite unexpected:
> because the isa bus is hanging off the pci bus, bus_release_resource()
> call by a isa device, eventually reaches the pci_release_resource(),
> where the device is blindly assumed to be a pci device and its isa_device
> struct overwritten as if it were a struct pci_devinfo. pci_release_resource()
> should check for pass-thru releases.
How about this patch:
Index: pci.c
===================================================================
RCS file: /home/ncvs/src/sys/pci/pci.c,v
retrieving revision 1.116
diff -u -r1.116 pci.c
--- pci.c 1999/08/28 00:51:03 1.116
+++ pci.c 1999/09/03 07:59:44
@@ -1375,40 +1375,42 @@
int rv;
struct pci_devinfo *dinfo = device_get_ivars(child);
pcicfgregs *cfg = &dinfo->cfg;
+ int passthrough = (device_get_parent(child) != dev);
int map = 0;
- switch (type) {
- case SYS_RES_IRQ:
- if (rid != 0)
- return EINVAL;
- break;
+ if (!passthrough)
+ switch (type) {
+ case SYS_RES_IRQ:
+ if (rid != 0)
+ return EINVAL;
+ break;
- case SYS_RES_DRQ: /* passthru for child isa */
- break;
+ case SYS_RES_DRQ: /* passthru for child isa */
+ break;
#ifdef __alpha__
- case SYS_RES_DENSE:
- case SYS_RES_BWX:
+ case SYS_RES_DENSE:
+ case SYS_RES_BWX:
#endif
- case SYS_RES_MEMORY:
- case SYS_RES_IOPORT:
- /*
+ case SYS_RES_MEMORY:
+ case SYS_RES_IOPORT:
+ /*
* Only check the map registers if this is a direct
* descendant.
*/
- if (device_get_parent(child) == dev)
- map = pci_mapno(cfg, rid);
- else
- map = -1;
- break;
-
- default:
- return (ENOENT);
- }
+ if (device_get_parent(child) == dev)
+ map = pci_mapno(cfg, rid);
+ else
+ map = -1;
+ break;
+
+ default:
+ return (ENOENT);
+ }
rv = BUS_RELEASE_RESOURCE(device_get_parent(dev), child, type, rid, r);
- if (rv == 0) {
+ if (!passthrough && rv == 0) {
switch (type) {
case SYS_RES_IRQ:
cfg->irqres = 0;
--
Doug Rabson Mail: dfr@nlsystems.com
Nonlinear Systems Ltd. Phone: +44 181 442 9037
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