DMA disabled by default for optical drives - why?

[James Gray]

On Tuesday 20 December 2005 07:39, Jason Smith wrote:
> After I have installed Ubuntu 5.10 I din't manage to write not even one
> DVD, because DMA was not enabled. Not to mention
> the high CPU usage when I was accessing my optical drive.
>
> Luckily Nero warned me about the DMA misconfiguration, I corected the
> problem
> and now everything works fine. I think DMA should be enabled by default.

All well-and-good, but what if the Ubuntu installer loads the ide-generic 
driver before your chipset-specific IDE driver resulting in a situation that 
setting DMA on any drive causes a kernel panic?  Not Ubuntu's fault mind you 
- it was a known gotcha with early Asus K8VSE motherboard BIOS'es..

So enable DMA by default and possibly panic the kernel if the BIOS is a little 
screwy, or play safe?  Personally, I'd rather have a machine that boots (even 
at sub-optimal speed) so I can fix the problem over a system that panics 
before it even reaches run level 1. :)  It's not just old hardware that can e 
flakey with DMA enabled by deafult - unfortunately.

Cheers,

James
-- 
If we won't stand together, we don't stand a chance.