I have a laptop with a chipset Intel 82845 845 (Brookdale) rev 04. If I try to activate the DMA with hdparm -d1 /dev/hda, I get the error message : HDIO_SET_DMA failed. Apparently it occurs because of a bios mismapping (see http://www.van-dijk.net/linuxkernel/200222/1021.html), the mandrake 8.2 boots with the same error message than reported in this thread : PCI: Device 00:1f.1 not available because of resource collision. This occurs only with Mandrake 8.2 and RedHat 7.3. There is no problem to activate DMA on this laptop with the Slackware 8.1 distribution, which installs the same 2.4.18 kernel. So I guess there is a patch for that issue. This is a very bad limitation : with mandrake my hard drive works at 5Mo/s, with Slackware, it works at 18Mo/s. This problem occurs also with cooker.
