Fwd: DMA problems in ide-scsi

["meaty biscuit" <meatybiscuit@gmail.com>]

I know there are lots of people that are glad to be done with
ide-scsi, but I'm hoping there is someone out there that has some
experience with this driver that my be able to help.  I would happily
switch modules and start using ide-cd, but I have a few pieces of
software that rely on ide-scsi to work properly and I don't have
enough time to change my software to work with ide-cd before my
product release deadline.

I am working with a mainline kernel, version 2.6.15.7 (I cannot change
kernel versions either).  If DMA is enabled and I try to write to a
CD, I get a kernel panic.  However, reading from a CD with DMA enabled
works fine.  If DMA is disabled and programmed IO is used, I can both
read and write CDs but the fact that PIO uses so much of the CPU
causes my application to have some problems and again, I don't have
time to go through several application release cycles to make them
work with PIO.

I have noticed that writing to CD (with DMA enabled) in 2.6.9 works
fine, it seems as though the breakage of ide-scsi occured in 2.6.10.
Also, burning a CD using DMA with ide-scsi in 2.6.19 seems to work as
well.  I have looked through the ide-scsi code for hours, and I have
also done a fair amount of debugging looking for the problem but I
have had no success.  I tried contacting Bartlomiej and have been
unsuccessful in getting a hold of him.  Does anyone know of a patch
floating around that may fix this problem?  Does anyone that is more
familiar with the ide, scsi, or dma subsystems have any suggestions
for me?  I am willing to put in the time and effort to fix this
problem and I would be more than happy to submit a fix back into the
open source world, but I am stuck and need any help I can get.

Thanks for your time.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/