[Pkg-libburnia-devel] Bug#789260: libburn4: Incompatibility with Plextor PX-608CU burner

[Thomas Schmitt]

Hi,

libburn might be contributing to high power consumption by
firing a lot of retried WRITE(10) commands to the yet-not-ready
drive. In the old days of CD burning, it was essential not to
let the drive buffer run empty.

But with DVD you could try to slow down the retries:

In  libburn/sg-linux.c  there is a code piece

        break;
                /* if ! done : loop for retry */;
        }

which could be changed to

        break;
                /* if ! done : loop for retry */;
                usleep(10000);
        }

Waiting 10 microseconds at DVD speed 16 would mean to delay
about 220 KB, which should be much less than the drive buffer
size. So there is a chance to catch up.
(Nevertheless the execution times of initial WRITE(10) commands
 indicate a maximum transfer speed of about 16000 KB/s = 12x DVD.)


Have a nice day :)

Thomas