DMA-aware drive runs at PIO since upgrading to 5.3beta

Søren Schmidt sos at
Thu Sep 9 07:54:52 PDT 2004

Mark Daniel Reidel wrote:
> Hi there!
> Since I upgraded from a current as of end of July to 5.3 beta2, I 
> noticed, that by CDRW now runs on PIO4 which is quite annoying, since it 
> was running on WDMA perfectly well before :o( My other drive, a DVD is 
> detected fine, here's the dmesg snip:

> Any idea why it's doing this? My other PC at work has a CDROM which is 
> also now run on PIO4 instead of DMA since the upgrade, so I guess it's 
> nothing specific to my hardware since I have an Athlon and a P4 at work.
> Any help would be appreciated, because burning at PIO4 is not what I'd 
> like to to from now on as you can imagine ;o)

We have changed the default to be DMA enabled on ATAPI devices. However 
for that to have a chance to work I changed the logic so we only enable 
DMA on UDMA33 capable ATAPI devices. This is because *lots* of old ATAPI 
device claim DMA but cant, only ollowing UDMA33 sorts out most if not 
all those buggy devices.
Now if you want DMA on your drive, just use atacontrol to set the mode 
you want.


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