Re: [LI] hdd problem?

[Arun Sharma <adsharma@xxxxxxxxxxxxxxx>]

On Sun, Nov 28, 1999 at 12:02:47PM +0530, XRDLAB wrote:
> I too have seen this message on my hard disk. Strangely, I get this
> only when I am using RH6.1. When I am running Debian, I do not see
> this message. I tried disabling the power saving features, etc and
> still ended up getting these frequently. As Arun suggested, I even ran
> badblocks on my disk and got no errors. 

Actually, I read the code some more and sounds like this could have
two reasons:

(a) Your drive doesn't conform to the timing constraints in the IDE 
    spec. From /usr/include/linux/ide.h:

#define WAIT_DRQ	(5*HZ/100)	/* 50msec - spec allows up to 20ms */

The error that you're seeing can happen if a read/write command is issued
to the IDE hardware and it doesn't respond in 50ms.

The relevant code is in: linux/drivers/block/ide.c (ide_wait_stat)

(b) It could also be because interrupts are enabled in the above code
    (ide__sti()) and some other device (may be the timer) interrupts the
    CPU many times and by the time all those interrupts are handled,
    the time's up and you've timed out. This is because the time out is
    based on jiffies. Also, looks like the code is susceptible to the
    jiffies overflow problem (though I remember Alan Cox having fixed a
    large number of such problems)

If you really feel like messing with it, try increasing WAIT_DRQ. Note
that I'm not exactly a hardware expert and the above reasoning is informed
speculation. You're probably better off searching linux-kernel archives
for the right keywords and following the discussion. Dejanews is your 
friend.

I'd love to hear your findings.

	-Arun

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