Re: [CFT] Bus mastering support for IDE CDROM audio

benh
2002-01-28T09:52:31Z

>At no stage does a packet-mode DMA error turn off drive-level
>DMA. This is because some devices seem to perform ordinary
>ATA DMA OK, but screw up packet DMA.
>
>The kernel internally retries the requests when it performs fallback,
>so userspace shouldn't see any disruption as the kernel works
>out what to do.
>
>Once the drive has fallen back to single-frame (or PIO mode) for
>packet reads, the only way to get it back to a higher level is
>a reboot.

Doesn that mean that a bad media (typically a scratched CDROM) will
cause the drive to revert to PIO until next reboot ?

Ben.