Re: More on the IDE multiwrite problem

Mark Lord (mlord@pobox.com)
Sat, 18 Dec 1999 11:33:22 -0500

Alan Cox wrote:
>
> I've been doing some more digging. Having been over the multiwrite code
> (with the io unlock fix in it) Im mystified what is going on.
..
> The error case appears to have a definite pattern. It is always
>
> multiwrite_intr status=0x50 (or 52) { DriveReady SeekCompete }
> buffer list corrupted
> [maybe a repeat of the error code]
> then either a crash or an I/O error log from end_request

Mmm.. are you sure about the status bits? There is no DRQ (datarequest).
I wonder if we are just responding incorrectly to the final "I/O complete"
interrupt or something? Because without the DRQ bit set, the drive is
NOT expecting any more output data.
..
> I'll keep on poking around the code. The obvious path for an error would
> seem to be
>
> hwgroup->wrq = *rq;
> ide_set_handler(drive, &multiwrite_intr, WAIT_CMD)
> -> IRQ here <-.
> multiwrite_intr gets an error
> completes the request
> => END IRQ <-
> ide_multiwrite ....
> BOOM!

But that path, and IRQ-masking etc.. doesn't seem to be any different
from before.. darn it! Mmm...

--
Mark Lord
Real-Time Remedies Inc.
mlord@pobox.com


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