HDIO_SET_DMA failed on a Dell Latitude C400 Laptop

[Mark Watts]

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I've just burnt a cd for the first time on a Dell Latitude C400 laptop and I 
noticed that the system was quite sluggish while the burn was happening. 
(mouse pointer erratic, window redraw slow etc).

Remembering a similar issue with a desktop system, I did the following to 
enable DMA on the hard drive (hdparm was giving ~3MB/sec read)

# hdparm -c1 -d1 /dev/hda

/dev/hda
 setting 32-bit IO_support flag to 1
 setting using_dma to 1 (on)
 HDIO_SET_DMA failed: Operation not permitted
 IO_support   =  1 (32-bit)
 using_dma   =  0 (off)


hdparm now reports ~7MB/sec which is better but still prety poor.


Any ideas why I couldn't set DMA on the drive?


CPU = Mobile Pentum 3 @1.2GHz (800MHz when booted with no power cord)
Ram = 256MB
HDD = IBM Travelstar (IC25N020ATDA04-0) 20GB
BIOS Rev = A12


- -- 
Mark Watts
Senior Systems Engineer
QinetiQ Trusted Information Management
Trusted Solutions and Services group
GPG Public Key ID: 455420ED

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