Messages in this thread | | | Date | Sat, 21 Aug 2004 12:32:09 +0200 | From | Jens Axboe <> | Subject | Re: serialize access to ide device |
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On Thu, Aug 19 2004, Bartlomiej Zolnierkiewicz wrote: > > 2.6 breaks really really easily if you have any traffic on a device and > > issue a hdparm (or similar) command to it. Things like set_using_dma() > > and ide_set_xfer_rate() just stomp all over the drive regardless of what > > it's doing right now. > > Yep, known problem.
Something should be done about it, it's pretty critical imho.
> > I hacked something up for the SUSE kernel to fix this _almost_, it still > > doesn't handle cases where you want to serialize across more than a > > single channel. Not a common case, but I think there is such hardware > > out there (which?). > > > > Clearly something needs to be done about this, it's extremely > > frustrating not to be able to reliably turn on dma on a drive at all. > > I'm just tossing this one out there to solve 99% of the case, I'd like > > some input from you on what you feel we should do. > > What about adding new kind of REQ_SPECIAL request and converting > set_using_dma(), set_xfer_rate(), ..., to be callback functions for this > request? > > This should be a lot cleaner and will cover 100% cases.
That will still only serialize per-channel. But yes, a lot cleaner.
-- Jens Axboe
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