RELENG_7: interrupt eating whole cpu core

[Dominic Fandrey]

Tom Evans wrote:
> On Fri, 2008-02-08 at 17:14 +0100, Dominic Fandrey wrote:
>> Tom Evans wrote:
>>> If I try to turn on DMA, I just get WDMA2, which just doesn't cut it:
>> I think any DMA mode is fast enough to handle a DVD drive. There's just no 
>> necessity for more.
>>
> 
> WDMA is not UDMA. Any UDMA variant would be enough. WDMA2 provides a
> maximum of 16MiB/s, which will frequently lead to buffer underruns
> viewing a DVD. UDMA2 provides a maximum of 33MiB/s, which IS plenty.

16MB/s is exactly what is needed for 12x DVD access. I think this is the usual 
speed for a Notebook drive nowadays and it suffices for me.

>>>> # atacontrol mode acd0 udma5
>>> current mode = WDMA2
>> Same as for me. I'm satisfied with the speed of the drive.
> 
> I'm rarely satisfied - I'm quite often not bothered enough to pursue :)

Well, if 12x speed is not enough for you, you have to use an external drive. 
This is not a driver issue. It's just what your drive supports.