Hi, I've a puzzling problem and hope someone's experience can help me. I have quite a recent Plextor 48/24/48 burner attached to my Linux system (currently 2.4.23-rc2)
This drive has been running initially with my kernel which enables DMA by default. Now I cannot use the drive anymore under such a kernel. readcd dev=0,1,0 -f /dev/null works but that's special cased since readcd dev=0,1,0 -f - | cat >/dev/null DOESN'T work and even a normal 'mount' doesn't work. Always, I see a DMA timeout error on kern.log. I've tried various things like the boot parameters acpi=off and I've connected the drive to the other cable of my VIA vt82c686a onboard controller. Nothing helped. Then I regenerated the kernel with the option 'DMA for disks only' and now I have no problems with the drive except a simple readcd now produces a system load of more than 90% (on an otherwise idle system) and the read speed drops to 4250 kb/s instead of 7056 kb/s as reported by readcd initially. Is my drive defect now (just the DMA logic) ? This occurred before and after upgrading the drive's BIOS to the most recent version. Or is it a Linux problem, but that's hard to believe since even an older kernel which has run fine with this drive doesn't run anymore with this drive. Any ideas and comments are more than welcome, -- Helmut Jarausch Lehrstuhl fuer Numerische Mathematik RWTH - Aachen University D 52056 Aachen, Germany