While trying to enable this setup, I found that my BIOS doesn't initialize
the secondary video card. This caused the matroxfb to crash when it tried
to access the Millennium II's framebuffer/registers.
After playing with the kernel, I could enable the memory for the secondary
video card with this piece of code from arch/i386/kernel/bios32.c ("dev"
is the secondary VGA card in question):
unsigned short cmd;
pci_read_config_word(dev, PCI_COMMAND, &cmd);
if (!(cmd & PCI_COMMAND_MEMORY)) {
printk("PCI: Enabling memory for device %02x:%02x\n",
dev->bus->number, dev->devfn);
cmd |= PCI_COMMAND_MEMORY;
pci_write_config_word(dev, PCI_COMMAND, cmd);
}
And this function would enable the secondary video card's bus mastering
capability:
pci_set_master(dev);
But the Matrox Millennium II is still not configured correctly.
It's IRQ is 0, and it's three base_address registers appear to be
suspiciously incorrect:
Memory at ff000000 (32-bit, prefetchable)
Memory at ffffc000 (32-bit, non-prefetchable)
Memory at ff800000 (32-bit, non-prefetchable)
The size of the memory regions are respectively:
0 is 16 megabytes
1 is 16 kilobytes
2 is 8 megabytes
Hmmm...
base_address[0] == -16MB
base_address[1] == -16KB
base_address[2] == -8MB
The size of each of these memory locations and where they are located in
memory cause ioremap to fail:
/*
* Don't allow mappings that wrap..
*/
if (!size || size > phys_addr + size)
return NULL;
I'm currently trying to figure out what to do next. Working inside the
kernel is rather new to me, and I don't know way around the PCI subsystem
either. So if I made a mistake, or you think I'm doing something wrong,
please enlighten me.
In short, any assistance would be greatly appreciated! :-)
I've appended the output of lspci -vvvxxx WRT the Millennium II for the
curious (the output is from an unmodificed 2.2.9 kernel).
davez
-- Dave Zarzycki http://thor.sbay.org/~dave/ http://www.sbay.net/
00:13.0 VGA compatible controller: Matrox Graphics, Inc. MGA 2164W [Millennium II] Subsystem: Unknown device 102b:1000 Control: I/O- Mem- BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- Status: Cap- 66Mhz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- Interrupt: pin A routed to IRQ 0 Region 0: Memory at ff000000 (32-bit, prefetchable) [disabled] Region 1: Memory at ffffc000 (32-bit, non-prefetchable) [disabled] Region 2: Memory at ff800000 (32-bit, non-prefetchable) [disabled] 00: 2b 10 1b 05 00 00 80 02 00 00 00 03 00 00 00 00 10: 08 00 00 ff 00 c0 ff ff 00 00 80 ff 00 00 00 00 20: 00 00 00 00 00 00 00 00 00 00 00 00 2b 10 00 10 30: 00 00 ff ff 00 00 00 00 00 00 00 00 ff 01 00 00 40: 00 01 00 5f 00 00 00 00 ff ff ff ff 00 00 00 00 50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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