Red Hat 7.1 Linux Beta - beta3
Feb 7, 2001
Failing HW: ML570, DL580
Passing HW: DL360, ML350, ML370, ML530 

More than one secondary bus for a given north bridge is not recognized.  
This leaves PCI slots that are inaccessible.

It appears that the following email and patch corrects the issue:

------------------------------------------
The patch below (against vanilla 2.4.0) makes Linux recognize
PCI-Devices sitting in another PCI bus than 0 (or 1).

This was tested on a Netfinity 7100-8666 using a ServerWorks chipset.


00:00.0 Host bridge: ServerWorks CNB20HE (rev 21)
00:00.1 Host bridge: ServerWorks CNB20HE (rev 01)
00:00.2 Host bridge: ServerWorks: Unknown device 0006
00:00.3 Host bridge: ServerWorks: Unknown device 0006
00:01.0 SCSI storage controller: Adaptec 7896
00:01.1 SCSI storage controller: Adaptec 7896
00:05.0 Ethernet controller: Advanced Micro Devices [AMD] 79c970 [PCnet 
LANCE] (rev 44)
00:06.0 VGA compatible controller: S3 Inc. Trio 64 3D (rev 01)
00:0f.0 ISA bridge: ServerWorks OSB4 (rev 4f)
00:0f.1 IDE interface: ServerWorks: Unknown device 0211
00:0f.2 USB Controller: ServerWorks: Unknown device 0220 (rev 04)
02:04.0 Ethernet controller: Digital Equipment Corporation DECchip 
21142/43 (rev 41)
02:06.0 RAID bus controller: IBM: Unknown device 01bd

The last two lines do not occur without the patch.


diff -ur linux-2.4.0/linux/arch/i386/kernel/pci-pc.c 
linux/arch/i386/kernel/pci-pc.c
--- linux-2.4.0/linux/arch/i386/kernel/pci-pc.c Thu Jun 22 16:17:16 2000
+++ linux/arch/i386/kernel/pci-pc.c     Tue Jan 16 18:10:30 2001
@@ -849,10 +849,13 @@
         * ServerWorks host bridges -- Find and scan all secondary buses.
         * Register 0x44 contains first, 0x45 last bus number routed there.
         */
-       u8 busno;
-       pci_read_config_byte(d, 0x44, &busno);
-       printk("PCI: ServerWorks host bridge: secondary bus %02x\n", 
busno);
-       pci_scan_bus(busno, pci_root_ops, NULL);
+       u8 busno_first, busno_last, i;
+       pci_read_config_byte(d, 0x44, &busno_first);
+       pci_read_config_byte(d, 0x45, &busno_last);
+       for (i = busno_first; i <= busno_last; i++) {
+               printk("PCI: ServerWorks host bridge: secondary bus %
02x\n", i);
+               pci_scan_bus(i, pci_root_ops, NULL);
+       }
        pcibios_last_bus = -1;
 }
 


Adam
-- 
Adam                 al10.de
  Lackorzynski         http://a.home.dhs.org
------------------------------------------

Reproducible: Yes.

Compaq Bug #: 194031

Compaq considers this defect a  MUST-FIX for Florence.