Re: Bug in 2.6.29 ide-cd: Kernel freeze: bisected + unacceptable workaround

Michael Roth
2009-03-31T12:35:54Z

>> take it ok. Also, if I remember correctly, the original ide-cd behavior
>> was to issue the command and _then_ start DMA so we're back to that. I
>> guess now we should be concerned whether the other ATAPI devices can
>> handle the reverse situation where you first issue a command and _then_
>> start DMA.. Hmm...
>
> Most devices don't care but you do need to follow the exact ATAPI spec.
> If you search way back through the archives you'll find long discussions
> on this during either 2.4 or 2.2 when HP hit problems caused by us
> turning DMA on too early.

AFAIK, the old bevavior was to start DMA _after_ issuing the command _only_
for CD-drives and for the remaining ide devices the other way around,
why not just restore the old behavior and do the DMA after command only
for CD-drives?