SB600 IDE SATA II but no DMA

[eneilsen]

I'm having a problem trying to enable DMA.
hdparm -d1 /dev/sda

/dev/sda:
setting using_dma to 1 (on)
HDIO_SET_DMA failed: Inappropriate ioctl for device


I googled the error and most of the threads I've read talked about "Compiling the chipset support into the kernel". I'm running the 2.6.22.1-41.fc7 kernel with kmod-fglrx 8.39.4

Anyone have any idea on how to fix this?





Motherboard:
ASUS M2A-VM HDMI motherboard that comes with an SB600 chipset.


lspci -v | grep IDE
00:14.1 IDE interface: ATI Technologies Inc SB600 IDE (prog-if 82 [Master PriP])

[mlau]

Are you sure the /dev/sda node refers to the
IDE controller you listed? (post a dmesg and
lspci output if possible)

The traditional "IDE-DMA" stuff does not at all
apply to newer SATA (read up on the history of
IDE to understand why), which would explain
the inappropriate IOCTL error.

[yoshi314]

hdparm cannot modify any settings on sata drives. it was designed to work on ata drives.

they (sata drives/motherboards) are said to be "smart enough" to use dma by default. if not, maybe sdparm will help here.

are you sure it doesn't work? try running hdparm -tT /dev/sda and post the results.

[Raven3x7]

Besides you are probably using libata which sets DMA modes automatically even for IDE afaik. It had a nasty bug in the .20 kernel that failed to set DMA on IDE Drives if a SATA Drive was present.

[eneilsen]

Yeah you guys are right,
hdparm -tT yeilds

cached reads: 665.27 MB/sec
buffered disk reads: 58.26 MB/s



I thought there was a problem because I am running a myth tv which records tv shows to the fedora 7 box. And then on my Windows XP box I connect to the a SMB share and stream the mpeg2 files. I've also tried xvid (avi) files and found that it's extremely slow. I'm getting about 80-200 kB/sec (using DU meter). Which is too slow to stream the 4 GB file.

What's interesting is when I open up a VNC window to the fedora 7 box. When I open up the vnc window and just leave it the vnc window viewing the linux desktop I can then stream the mpeg or avi file at 3.61mB/sec. It makes no sense I have no idea what's going on. If I lower the vnc window (minimize the vnc screen) the streaming slows back down to 100 kB/sec and the video (winamp) starts stuttering. As soon as I restore the vnc window the video plays smoothly and the streaming bit rate resumes.

FYI when I kill winamp the du meter reports the bandwidth to be 0.8 - 2 mB/sec.

I would really like close down the vnc viewer, but it's unwatchable without it. Does anyone have any idea what's going on and how to fix the problem.