Re: UDMA(33)/(66) or What the heck is going on?

From: Andre Hedrick (andre@linux-ide.org)
Date: Mon Jun 26 2000 - 00:27:15 EST


Because you did not get validity bit checks to pass.
Therefore you must compile in overrides and assume responsiblity.

On Sun, 25 Jun 2000, Erick Kinnee wrote:

> Using all of the earlier 2.4.0-test1-ac* patches dmesg reported UDMA(33)
> on my hda, it never printed a message about hdb. Now it did set hdb to
> udma4 per hdparm, so I knew it was doing UDMA(66). I changed to
> ac22-riel and now i get:
>
> Uniform Multi-Platform E-IDE driver Revision: 6.31
> ide: Assuming 66MHz system bus speed for PIO modes

66MHz is stupid! on an ATA-bus......
RTFSC!

You get 25/33/37/41 MHz for the "idebus speed" Nowhere can you find
clockings for 66MHz.

You should be damn lucky the code is smarter than the user or you would
have vaporized your disk!

Yes, I have had one case where this happened and this the code is smarter
to prevent this from happening again.

> VP_IDE: IDE controller on PCI bus 00 dev 39
> VP_IDE: chipset revision 6
> VP_IDE: not 100% native mode: will probe irqs later
> VT 82C691 Apollo Pro
> Chipset Core ATA-66
> Split FIFO Configuration: 8 Primary buffers, threshold = 1/2
> 8 Second. buffers, threshold = 1/2
> ide0: BM-DMA at 0xe000-0xe007, BIOS settings: hda:DMA, hdb:DMA
> ide0: VIA Bus-Master (U)DMA Timing Config Success
> ide1: BM-DMA at 0xe008-0xe00f, BIOS settings: hdc:DMA, hdd:DMA
> ide1: VIA Bus-Master (U)DMA Timing Config Success
> hda: Maxtor 90680D4, ATA DISK drive
> hdb: Maxtor 90650U2, ATA DISK drive
> hdc: Memorex CRW-1622, ATAPI CDROM drive
> hdd: FX240S, ATAPI CDROM drive
> ide0 at 0x1f0-0x1f7,0x3f6 on irq 14
> ide1 at 0x170-0x177,0x376 on irq 15
> hda: 13281408 sectors (6800 MB) w/256KiB Cache, CHS=826/255/63, UDMA(33)
> hdb: 12594960 sectors (6449 MB) w/2048KiB Cache, CHS=784/255/63, UDMA(33)
> Partition check:
> hda: hda1 hda2 hda3
> hdb: hdb1 hdb2
>
>
> now you can see that it reports UDMA(33) during boot, and hdparm
> confirms that they are both doing udma2. And you can't force hdb to
> udma4 with hdparm.

See above and take responsiblity for you decision to override safety.

Andre Hedrick
The Linux ATA/IDE guy

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