Booting YDL 2.1 on B&W G3 Problems

[Bill Fink]

On Sun, 30 Jun 2002, "Timothy A. Seufert" wrote:

> At 12:33 AM -0400 6/30/02, Bill Fink wrote:
> 
> >>  The reason you aren't having problems when you eliminate the CMD64X
> >>  driver is presumably that the generic IDE driver can't enable UDMA
> >>  mode.  It might not even be able to enable DMA.
> >
> >Actually, being somewhat paranoid after all the severe problems I had
> >run into, I finally removed the original internal drive to avoid any
> >further problems.  I do have the CMD64X driver disabled in the current
> >kernel:
> >
> >astro% dmesg | grep CMD
> >CMD646: IDE controller on PCI bus 01 dev 08
> >CMD646: detected chipset, but driver not compiled in!
> >CMD646: chipset revision 5
> >CMD646: 100% native mode on irq 26
> >
> >Is using_dma as reported by hdparm the same thing as the UDMA mode
> >you were talking about?  If so, it still seems to be set on the new
> >drive:
> 
> Not necesssarily.  It might be using the slower 16.6 MB/s DMA mode 
> (multiword DMA mode 2) instead of 33.3 MB/s UDMA.  If I recall 
> correctly, corruption only happens in UDMA mode.

The dmesg output seems to indicate it's using UDMA mode.

astro% dmesg | grep -i dma
    ide0: BM-DMA at 0x1050-0x1057, BIOS settings: hda:pio, hdb:pio
    ide1: BM-DMA at 0x1058-0x105f, BIOS settings: hdc:pio, hdd:pio
hda: 78165360 sectors (40021 MB) w/2048KiB Cache, CHS=77545/16/63, (U)DMA
hde: Enabling MultiWord DMA 2
ide_pmac: MDMA, cycleTime: 120, accessTime: 75, recTime: 45
ide_pmac: Set MDMA timing for mode 2, reg: 0x00211526
hde: ATAPI 10X CD-ROM drive, 128kB Cache, DMA
PowerMac Burgundy  DMA sound driver rev 016 installed

> >According to your theory, it would seem all that would be necessary to
> >workaround the problem would be to issue an "hdparm -d 0" on the drive(s).
> >If I get some spare time, I may test that theory, but as much time as I've
> >already wasted on that system, it's not real high on my priority list,
> >especially since it seems to be working pretty well finally.
> 
> Yes, that should do it.  No guarantees, but I don't remember ever 
> seeing a problem with DMA off.  Not using UltraDMA mode should also 
> do the trick.  Use:
> 
> hdparm -X34 /dev/hdX
> 
> to select multiword DMA mode 2.  -X66 selects UDMA mode 2.

Yes, that would be better than completely turning off DMA.

> Also, back when I was trying to get my B&W working right, I wrote a 
> simple program that tests for disk I/O corruption by writing large 
> files to disk and then reading them back and verifying them.  Better 
> than writing real data to disk and having to find out later that it 
> got corrupted.  :)  If you want it, let me know and I'll send you the 
> C source code.

Sure, I always like having simple test tools to check out various parts
of the system.

						-Thanks

						-Bill