Messages in this thread | | | Date | Thu, 18 Dec 1997 08:50:06 -0500 | From | mlord <> | Subject | Re: UDMA |
| |
Boris Seifert wrote: > > On Dec 17, 21:57, mlord wrote: > > > The 32-bit IO and multcount work only for PIO, not DMA. > > On some drives (?), multcount might even slow down DMA, > > though there is no evidence to support this theory. > > Neither of these buys anything when DMA is used. > > How come it (seems to) work here ? > > [root@clito /root]# hdparm /dev/hda > > /dev/hda: > multcount = 0 (off) > I/O support = 1 (32-bit) <---here > unmaskirq = 0 (off) > using_dma = 1 (on) <---and here
In this case, "32-bit" I/O is not actually "working". Sure, it's enabled, but having zero effect..
The concept of multcount and "32-bit" I/O just plain has nothing to do with DMA transfers. No positive effect. -- mlord@pobox.com The Linux IDE guy
| |