RELENG_7: interrupt eating whole cpu core

[Tom Evans]

On Fri, 2008-02-08 at 19:35 +0100, Dominic Fandrey wrote:
> 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.

The chipset supports UDMA6, the drive supports UDMA6, I should be happy
with WDMA2 because 'thats what works'? Thanks for your 'help'. I'll
continue on here from myself.
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