No DMA on disks (Asus K8VSE Deluxe motherboard)

MFA

Hi,

The DMA on my disk(s) aren't running. The fact that DMA isn't enabled is obvius when you look at the poor preformance, and because reiserfs.fsck warns me that DMA is disabled..

So I tried doing a `hdparm -d1 /dev/hdb` (yes, /dev/hdb _is_ my main disk), but I get a

--
hdparm -d1 /dev/hdb

/dev/hdb:
setting using_dma to 1 (on)
HDIO_SET_DMA failed: Operation not permitted
using_dma = 0 (off)
--

And I'm pretty sure DMA is enabled in the kernel (Gentoo-2.6.10), because a quick grep thourgh the config file of the kernel gives::

--
cat /usr/src/linux/.config|grep -i dma
CONFIG_GENERIC_ISA_DMA=y
CONFIG_BLK_DEV_IDEDMA_PCI=y
CONFIG_BLK_DEV_IDEDMA_FORCED=y
CONFIG_IDEDMA_PCI_AUTO=y
# CONFIG_IDEDMA_ONLYDISK is not set
CONFIG_BLK_DEV_IDEDMA=y
# CONFIG_IDEDMA_IVB is not set
CONFIG_IDEDMA_AUTO=y
--

So now I'm lost... a chance me be that the chipset is unsupported, but before a kernel-upgrade DMA worked, so now I just don't know which module to load in order to regain DMA on my disk? - anyone know?

Morten Fangel
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Morten Fangel - Fangel

moocha · Watchman Joined: 21 Oct 2003 Posts: 5722

Well, which chipset are you using?
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MFA · Posted: Tue Apr 12, 2005 5:43 pm Post subject:

Hmm, not sure which one of them is for the disks, but the following two:

VIA K8T800
VIA VT8237
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Morten Fangel - Fangel

NeddySeagoon · Posted: Tue Apr 12, 2005 5:52 pm Post subject:

MFA,

Probably neither of them.

Can you do a lspci and post the line(s) with IDE in please?
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NeddySeagoon

Computer users fall into two groups:-
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moocha · Watchman Joined: 21 Oct 2003 Posts: 5722

VT8237 is the south bridge, which includes the IDE controller. Disable the generic IDE stuff (Generic/default IDE chipset support and Generic PCI IDE Chipset Support) since it slows things down, and enable CONFIG_BLK_DEV_VIA82CXXX (VIA82CXXX chipset support ). Do not compile it as a module. Build it into the kernel.
_________________
Military Commissions Act of 2006: http://tinyurl.com/jrcto

"Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety."
-- attributed to Benjamin Franklin

MFA · Posted: Tue Apr 12, 2005 5:54 pm Post subject:

Well, I don't know if it actually is one of them, but i did a grep for "via" in the kernel-config, and found out that "CONFIG_BLK_DEV_VIA82CXXX" wasn't set, so I simply enabled it (with [y]) and now it works...

great
_________________
Morten Fangel - Fangel

MFA · Posted: Tue Apr 12, 2005 5:57 pm Post subject:

moocha -> yep, you were right, the VIA module (well, not not as a module, but still) did the trick... I might try out the disabling of the Generic IDE one day, but for now, this is great... a rough test (can't remember the original measures)

Before:
Timing cached reads: 2316 MB in 2.00 seconds ~= 1050 MB/sec
Timing buffered disk reads: 120 MB in 3.01 seconds ~= 6.5 MB/sec

After:
Timing cached reads: 2316 MB in 2.00 seconds = 1155.86 MB/sec
Timing buffered disk reads: 120 MB in 3.01 seconds = 39.90 MB/sec

So a nice improvement..

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Morten Fangel - Fangel