[Tech] domande..amenità..:-)

[Vanni Guarnieri]

Da:

http://www.tux.org/lkml/#s13-3 (e' una FAQ)


ciao,
	vanni



3. Why does my kernel report lots of "DriveStatusError BadCRC" messages?
              (REG, contributed by Mark Hahn) You may see messages like:

kernel: hda: dma_intr: status=0x51 { DriveReady SeekComplete
Error }
kernel: hda: dma_intr: error=0x84 { DriveStatusError BadCRC}

In UDMA modes, each transfer is checksum'ed for integrity
(like Ultra2 SCSI, and more robust than normal SCSI's parity checking).
When a transfer fails this test, it is retried, and this warning is
reported. Seeing these warnings occasionally is not unusual or even a bad
thing - they just inflate your logs a little. If this really bothers you,
you can comment out the warning in the driver.

Seeing lots of these warnings (multiple per second) is
almost certainly a sign that your IDE hardware is broken. For reference,
all IDE must:
                    have a cable length of 18" or less
                    have both ends plugged in (no stub)
                    be 80-conductor cable if you're using a mode > udma33.
              IDE modes are generally also generated from the system
clock, so if you're overclocking (for instance, running AGP at 75 MHz),
you're violating IDE
              specs, and should not expect correct behavior. Similarly,
it's possible for your controller's driver to get timing parameters wrong,
but this is certainly not
              the first explanation to adopt.