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author | Ralf Baechle <ralf@linux-mips.org> | 2006-02-14 16:23:57 +0000 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@suse.de> | 2006-03-23 14:35:12 -0800 |
commit | bbe8f9a3e76c551973ee739de10b26581d78b45f (patch) | |
tree | 757788e67781a3eaee3453af79abf6bb50b3a681 /drivers/pci/probe.c | |
parent | 92c05fc1a32e5ccef5e0e8201f32dcdab041524c (diff) | |
download | op-kernel-dev-bbe8f9a3e76c551973ee739de10b26581d78b45f.zip op-kernel-dev-bbe8f9a3e76c551973ee739de10b26581d78b45f.tar.gz |
[PATCH] PCI: Avoid leaving MASTER_ABORT disabled permanently when returning from pci_scan_bridge.
> On Mon, Feb 13, 2006 at 05:13:21PM -0800, David S. Miller wrote:
> >
> > In drivers/pci/probe.c:pci_scan_bridge(), if this is not the first
> > pass (pass != 0) we don't restore the PCI_BRIDGE_CONTROL_REGISTER and
> > thus leave PCI_BRIDGE_CTL_MASTER_ABORT off:
> >
> > int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev * dev, int max, int pass)
> > {
> > ...
> > /* Disable MasterAbortMode during probing to avoid reporting
> > of bus errors (in some architectures) */
> > pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &bctl);
> > pci_write_config_word(dev, PCI_BRIDGE_CONTROL,
> > bctl & ~PCI_BRIDGE_CTL_MASTER_ABORT);
> > ...
> > if ((buses & 0xffff00) && !pcibios_assign_all_busses() && !is_cardbus) {
> > unsigned int cmax, busnr;
> > /*
> > * Bus already configured by firmware, process it in the first
> > * pass and just note the configuration.
> > */
> > if (pass)
> > return max;
> > ...
> > }
> >
> > pci_write_config_word(dev, PCI_BRIDGE_CONTROL, bctl);
> > ...
> >
> > This doesn't seem intentional.
Agreed, looks like an accident. The patch [1] originally came from Kip
Walker (Broadcom back then) between 2.6.0-test3 and 2.6.0-test4. As I
recall it was supposed to fix an issue with with PCI aborts being
signalled by the PCI bridge of the Broadcom BCM1250 family of SOCs when
probing behind pci_scan_bridge. It is undeseriable to disable
PCI_BRIDGE_CTL_MASTER_ABORT in pci_{read,write)_config_* and the
behaviour wasn't considered a bug in need of a workaround, so this was
put in probe.c.
I don't have an affected system at hand, so can't really test but I
propose something like the below patch.
[1] http://www.linux-mips.org/git?p=linux.git;a=commit;h=599457e0cb702a31a3247ea6a5d9c6c99c4cf195
[PCI] Avoid leaving MASTER_ABORT disabled permanently when returning from pci_scan_bridge.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/pci/probe.c')
-rw-r--r-- | drivers/pci/probe.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 63751a2..3bc0fcd 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -456,7 +456,7 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev * dev, int max * pass and just note the configuration. */ if (pass) - return max; + goto out; busnr = (buses >> 8) & 0xFF; /* @@ -466,12 +466,12 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev * dev, int max if (pci_find_bus(pci_domain_nr(bus), busnr)) { printk(KERN_INFO "PCI: Bus %04x:%02x already known\n", pci_domain_nr(bus), busnr); - return max; + goto out; } child = pci_add_new_bus(bus, dev, busnr); if (!child) - return max; + goto out; child->primary = buses & 0xFF; child->subordinate = (buses >> 16) & 0xFF; child->bridge_ctl = bctl; @@ -496,7 +496,7 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev * dev, int max bus ranges. */ pci_write_config_dword(dev, PCI_PRIMARY_BUS, buses & ~0xffffff); - return max; + goto out; } /* Clear errors */ @@ -505,7 +505,7 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev * dev, int max /* Prevent assigning a bus number that already exists. * This can happen when a bridge is hot-plugged */ if (pci_find_bus(pci_domain_nr(bus), max+1)) - return max; + goto out; child = pci_add_new_bus(bus, dev, ++max); buses = (buses & 0xff000000) | ((unsigned int)(child->primary) << 0) @@ -581,8 +581,6 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev * dev, int max pci_write_config_byte(dev, PCI_SUBORDINATE_BUS, max); } - pci_write_config_word(dev, PCI_BRIDGE_CONTROL, bctl); - sprintf(child->name, (is_cardbus ? "PCI CardBus #%02x" : "PCI Bus #%02x"), child->number); while (bus->parent) { @@ -601,6 +599,9 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev * dev, int max bus = bus->parent; } +out: + pci_write_config_word(dev, PCI_BRIDGE_CONTROL, bctl); + return max; } |