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

Alan Cox
2009-03-31T11:55:49Z

> 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.