2.4.19 stops at booting when I change PCI slot of a card

[Roman Dementiev <dementiev@mpi-sb.mpg.de>]

I searched for relevant problems, but without success.

I have Supermicro P4DPE motherboard, 2-Xeons and four Ultra100 TX2 PCI
IDE conrollers.

The motherboard has several PCI buses. Mapping of PCI slots to the buses
is the following:

PCI Slot 1-3 (66 Mhz):  bus 5 (bus number reported by linux startup
messages)
PCI Slot 4   (66 Mhz):  bus 6
PCI-X Slot 5 (66 Mhz):  bus 3
PCI-X Slot 6 (100 Mhz): bus 2

PCI-X slots configured as plain PCI
100 Mhz slot configured to function at 66 Mhz

When I plug in 4 cards into slots 1-4 or 1-3 and 5 everything is fine,
Linux boots, I have ULTRA DMA 100 on each of them.

But I wanted to avoid bus bandwith saturation moving each controller to
the separate bus (now I can't get more then 240 Mb/s with 8 disk. With 4
disks parallel read rate is 190 Mb/s, seems to be bottleneck in the PCI
bus).

It failed (none of configurations except 1-4 and 1,2,3,5 work) linux
stops after the message, corresponding to the last controller (other
controllers are also reported):

PDC20268: IDE controller on PCI bus 06 dev 08
PDC20268: chipset revision 2
PDC20268: not 100% native mode: will probe irqs later
PDC20268: (U)DMA Burst Bit DISABLED Primary MASTER Mode Secondary MASTER
Mode.
PDC20268: FORCING BURST BIT 0x50 -> 0x51 INACTIVE
    ide8: BM-DMA at 0x4000-0x4007, BIOS settings: hdq:pio, hdr:pio
    ide9: BM-DMA at 0x4008-0x400f, BIOS settings: hds:pio, hdt:pio


Any ideas? Where is problem?