ogle, dvd and hdparm

[tristure]

Hi,

I’m experiencing problems with my DVD drive. Here’s the situation.


After a fresh Gentoo installation I emerged Ogle (with USE dvd alsa).

Then I tried to run ogle : I got an error concerning /dev/dvd : the device did not exist. So I created the link to /dev/cdroms/cdrom0.

I ran Ogle again. It worked but the playback is very choppy and jumpy. I tried ogle –u cli /dev/cdroms/cdrom0 to avoid the symlink, but it doesn’t change anything.

I noticed that the console output tells me that « No Accelerated IMDCT transform » is found, then it prints a lot of « #### ! ! ! ! » with some occasional framerate indication ?

What’s IMDCT exactly ? Might there be a problem with this?

Another possibility is found by reading the forums is a DMA issue. My situation there is very confusing.

My kernel is built with the « force DMA » option on, and the « DMA for disks only » option turned off.
The devfsd.conf has got a line like « all_args=d1 » which if I understand correctly chould enable dma for everything.

Yet I discovered that I’ve got no /dev/hdc nor /dev/hdd (they should exist and represent my dvd and cd-rw drives !). Should I create symlinks or should they really be block device files ?

Very strange again, I can’t seem to hdparm my dvd drive : hdparm /dev/dvd or hdparm /dev/cdroms/cdrom0 return a « /dev/xxx not supported by hdparm ».

Last thing : my /proc/ide/hdc/settings and /hdd/settings show a « enable DMA : 0 », but even as root I can't modify this ? ! ? (And anyway my hdc and hdd don’t seem to exist ? ! ? ».

Sorry for my somewhat blurry explanations, but I’m very very confused with this situation, I really can’t figure out what’s happening.
So if you got ideas or hints to help me sort this out I would be very grateful !

Thanks a lot !

[ben]

Hi,

Most likely, your drive are under the scsi emulation, and this somehow prevent hdparm to enable dma.
If this is the case, you can turn off scsi emulation (in the kernel, or by unloading ide-scsi and loading ide-cd). Then both drive will appear as /dev/hdx and be ready for dma.

CD burning is now no problem anymore with ATAPI (no scsi-emulation) drive.

HTH,

Ben

[tristure]

dma was the problem. Turning off scsi emulation did the trick. Thanks!

Yet I wonder why I had no problem on previous installations, with scsi emulation on for burning and yet good dvd playback?

Well, whatever, now I'll have to find some good tutorial for atapi burning!!