RE: clock drift with two Promise Ultra133 TX2 (PDC 20269) cards

["Drew Winstel" <DWinstel@Miltope.com>]

Hello,


>I'm running 2.6.11.8 on an server with two Promise Ultra133 TX2 (PDC20269)
>PCI cards, same hardware revision (judging from stickers on the cards).
>I'm using the CONFIG_BLK_DEV_PDC202XX_NEW driver.
>Each card has two connected hard drives. Whenever I read from a disk
>on one of the cards (e.g. using 'dd if=/dev/hdX of=/dev/null bs=1M'), and
>at the same time read from a disk on the other card, there is heavy
>software clock drift. It drifts about 2-5 seconds per minute.

>This does not happen if I read from two drives connected on the same
>card, or if I read from a drive connected to the motherboard IDE
>(VIA vt8233a) and a drive on either of the Promise cards.

>Oskar Liljeblad (oskar@osk.mine.nu)

Just to verify your setup:

You have a total of four hard drives connected to your PDC20269, hde, hdg, 
hdi, and hdk, correct?

Are all four drives running in DMA mode?

Please post the output of lspci -vv and hdparm run on each of the four hard 
drives.

Also, you may want to try downloading and using Albert Lee's pata_pdc2027x 
driver (part of libata-dev-2.6 tree).  See info at my thread from earlier:
http://marc.theaimsgroup.com/?l=linux-ide&m=110902518625384&w=2

Download the latest libata-dev patch set at 
http://www.kernel.org/pub/linux/kernel/people/jgarzik/libata/

Hope this gets you started.

Drew
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