DMA issue in 2.6.12 ???

[Ardo van Rangelrooij <ardo@debian.org>]

Hi,

I ran into an interesting DMA issue in 2.6.12 vs. 2.6.11:

First some info on the system I'm running the latest and greatest sid on:

  Asus A8V Deluxe
  AMD Athlon64 3000+
  1G dual channel DDR (2x512MB)
  /dev/sda = Maxtor 6B200M0
  /dev/hda = Sony DVD-ROM DDU1622
  /dev/hdb = WDC WD1200JB-75CRA0
  /dev/hdc = Maxtor 6B200R0
  /dev/hdd = WDC WD1200JB-00EVA0

  /dev/sda has / and swap
  /dev/hdb and /dev/hdd are in /dev/md0 as raid-1

When using 2.6.11-9 everything is ok and as expected: The DMA flags are set
when running `cat /proc/ide/hd[bcd]/settings`, running `hdparm -T` gives
1800+ MB/sec, and running `hdparm -t` gives 45MB/sec for /dev/md0 and 54MB/sec
for /dev/hdc.  So far so good.

However, when running 2.6.12-1 things are not as expected: The DMA flags are
not set, and running hdparm I get much lower numbers.  And I get

    > hdparm -d 1 /dev/hdc

    /dev/hdc:
    setting using_dma to 1 (on)
    HDIO_SET_DMA failed: Operation not permitted
    using_dma    =  0 (off)
   
When booting nothing in the log files indicates something's wrong or whatever.   

Anybody any thoughts?

Thanks,
Ardo
-- 
Ardo van Rangelrooij                                     Debian XML/SGML Group
<ardo@debian.org>              <debian-xml-sgml-devel@lists.alioth.debian.org>
http://people.debian.org/~ardo/      http://debian-xml-sgml.alioth.debian.org/