Messages in this thread | | | Date | Thu, 25 Nov 2004 08:56:46 +0100 | From | Jens Axboe <> | Subject | Re: Re: Is controlling DVD speeds via SET_STREAMING supported? |
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On Wed, Nov 24 2004, Thomas Fritzsche wrote: > Hi David, > > I had the same problem with my DVD+-RW NEC-ND 3500 (NEC-support told me > that they didn't support linux :-( ). After googling I couldn't find an > answer. Because I didn't know anything about ide-cd (yesterday ;-)) I > read in this spec about the SET STREAMING command: > ftp://ftp.avc-pioneer.com/Mtfuji_4/Spec/Fuji4r10.pdf > If you also read the newer Specs (Mtfuji_5) then you'll find out that the > "SET CD SPEED" command is "only applicable to CD-R/RW logical units". > It looks like older DVD-Drives also support this command, but newer do not > support this for DVD+-R. But there is also the SET STREAMING command as > Jens Axboe described on this list. Not all devices support this feature > but my NEC-CD 3500 does (as I found out ;-) / my Teac-CD-RW does not) > > I wrote a little programm to test this SET STREAMING command (quick & > dirty). In my opinion it would make sence to also enhance the kernel > function cdrom_select_speed (linux/drivers/ide/ide-cd.c), so that this > function works also for "newer" DVD-drives. > (!first check for the Realtime-Streaming-Feature and then use the right > command to set the speed). Because DVD+-RW Drives will be faster (AND > LOUDER!!) very soon it would be nice to have this in the kernel.
I agree, I'll do a patch for this right now. Your example code looks fine. My only worry is that some drives might complain if your end_lba is larger than the capacity, I'll have to double check the spec.
-- Jens Axboe
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