[Libburn] Re: FYI: my current modifications versus CVS of 8 Dec

[scdbackup at gmx.net]

Hi,

> > i just had the opportunity to test my timeout patch
> > with the DMA-ill DVD-ROM and a 2.6.14 kernel.
> > ...
> > If i didn't know that the DVD-ROM is ill then
> > i would have had to search for quite a while.
> 
> Can you mount and read cd/dvd media normally with DMA enabled?

Half and half. (see below)

 
> Are we dealing with a piece of hardware that's too brain damaged to live?

Yes. It is brain damaged. It is a DVD-ROM that has nothing
to do with burning. It starts up with DMA on. If i use it for
reading then i get a few funny lines in /var/log/messages 
and DMA is off.
That's why i say "half and half". The Linux kernel solves the
problem in its own very rough way.

That DVD-ROM  is only an example for my problem with libburn drive 
scan as it is now. 
The same problem is caused by the (quite sane) LG DVD burner when
it is busy. So if i had two writers then i could not start up 
libburn for the second one as long as the first one is burning.
(Run test/burniso with a large file and try test/devices at
the same time in order to see a preview of the problem.)


> If it's just that specific drive that doesn't work, then it should be 
> replaced...

I should have replaced it when it went ill. It was a bit strange
from start and in september 2004 when i tested use of DVD-RW it
went over the edge.
It is a good CD-ROM reader in PIO mode while my burner is unable
to read old 30k-padded CD-RW up to the end. So i kept it.

All is fine if it is not touched by any CD writing process.


> What make/model of drive is it?

Some LG ... hwinfo | grep HL-DT ... now i got a traffic
jam at the DVD/CD writer ... 
... Wow ... about 150x writing speed with the last
200 MB of the test write ... holy moly.

That looks like the first real misburn via libburn.
Note to myself: Never execute  hwinfo  while burning.

Here it is:
  hdd: HL-DT-STDVD-ROM GDR8162B, ATAPI CD/DVD-ROM drive


But as said, it is the concept of mandatory bus scan which opens
the door for lots of trouble.
My whitelist patch saves me from that trouble in most situations.
It cannot save me, though, if i *want* a bus scan for configuration
purposes. Then i would need some hint about the address of offending
devices. (I failed to help myself with this problem.)


Have a nice day :)

Thomas


PS: 
I had to reboot after that hwinfo-libburn collision.
My burner was willing to write a new CD-RW afterwards and 
behaved normally. The finished media is recognized by libburn
as BURN_DISC_FULL but neither the burner nor the DVD-ROM drive
can read a single byte from it. I tested two more media. Same.

cdrecord dev=0,0,0 -reset  did not help. reboot did. Ewww.
See what i suffer for progress. :))