CD and DVD drives

**sakiZ** · 06-02-2005, 02:01 PM

Hi Markus,

I thought I'd touch base with you and tell you that (knock on wood) the DVD problem seems to be resolved.

While I think the noapm addition to the lilo.conf file was necessary, a few weeks later the screen went blurry for a second or two and then lost the usb-DVD drive.

I changed the memory timings in the bios to their most conservative settings. I had read somewhere one should do that to ensure the host USB card works properly. Willing to try anything, I did that and so far...... no more problems.

Nice to know the problem was not really Knoppix, but resided at a deeper level.

sakiZ

**Markus** · 06-02-2005, 09:30 PM

Glad you got it sorted out. One more thing to try would have been removing usb legacy support in bios, but if it works now, don't tweak it

**Keithj** · 06-10-2005, 09:57 PM

Markus - MANY thanks! Cured my CDROM woes at a stroke. Brilliant.

**sakiZ** · 09-24-2005, 02:47 AM

Hi Markus,

Long time since I checked in with you. Over the course of many weeks and months, I've been plumbing the depths of my Knoppix install and found the offending APM driver that I've sent posts to you about.

It's:

/usr/X11R6/lib/modules/drivers/apm_drv.o

Whenever this driver would activate, it would bring down my USB storage so I could not read my external USB DVD drive as you may remember.

Apparently there are different levels to apm, the one above being geared toward working the GUI environment.

To make a long story short, I disabled this driver by renaming it. Now I have no more errant apm problems that bring down my USB DVD drive. No more cheat codes needed for apm. I only use acpi=force now.

The screen still goes blank after sitting a long time and I have no problems on shut down so I wonder how critical that driver is. Apparently not very. And of course, I have no problems with my DVD drive. I can't say to this day I understand the connection.

An unexpected thing happened after I disabled it. My HD performance went up. Buffered disk reads went from 38 to 42+ mbytes. The whole system seems a little snappier.

I hope this helps someone else.

sakiZ

**Markus** · 09-24-2005, 11:04 AM

If you do a "locate apm" you'll find stuff like /etc/apm/event.d/20hdparm and /etc/devfs/conf.d/apm
The first one possibly explains hd performance.
I suppose you don't have power control in kcontrol -> Peripherals -> Display? Finally, some monitors have their own power saving. Can't really be of much help there.
A few more thing to try is "xset s off", see man xset for what it does, and "setterm -blank 0". If one works, add to some x startup script or where you wish. They're really workarounds and not taking care of whatever powers down the display, but OTOH it shouldn't matter as long as it works like you want

**sakiZ** · 10-06-2005, 06:27 PM

Well, first the good news. After tinkering with my module conf file for the 2.6.9 kernel I am able to boot into the 2.6.9 kernel on my Knoppix 3.7 HDD install. Wow. I never thought that would happen. I about fell off my chair.

I wanted to see if my external USB DVD-rw drive could be found. After doing a "lsusb" I discovered Linux does see the USB External DVD-rw drive as an "sda" mass storage device. I was expecting an "scr2" or similar. Hmm.

Although I went ahead and made a mount point for the drive called "DVD-USB-Storage" in fstab, and I can mount and read the drive like this, it's not what I was really looking for as K3b does not see it as a writeable drive. So, it is usable to pull info off the DVDs I have made as backups. But no more than that.

So, for the time being I'll just keep using the 2.4 kernel.

Any thoughts on this?

sakiZ

**Markus** · 10-06-2005, 07:51 PM

That could be just a problem with scsi devices on 2.6.9, note that on 2.6.8 cdrecording itself is quite broken. I'd try a newer kernel as 2.6.9 is old anyway. If you have an older 2.6.7 lying around it should work as well. Nothing wrong with 2.4 series of course.