Gentoo Websites Logo
Go to: Gentoo Home Documentation Forums Lists Bugs Planet Store Wiki Get Gentoo!
Bug 167726 - kernel patch for dma on ICH6_5 / 82801FB Mobile chipset
Summary: kernel patch for dma on ICH6_5 / 82801FB Mobile chipset
Alias: None
Product: Gentoo Linux
Classification: Unclassified
Component: [OLD] Core system (show other bugs)
Hardware: x86 Linux
: High normal (vote)
Assignee: Gentoo Kernel Bug Wranglers and Kernel Maintainers
Depends on:
Reported: 2007-02-20 09:01 UTC by Christopher Friedt
Modified: 2007-03-10 11:39 UTC (History)
0 users

See Also:
Package list:
Runtime testing required: ---


Note You need to log in before you can comment on or make changes to this bug.
Description Christopher Friedt 2007-02-20 09:01:06 UTC
Hi Gentoo Kernel folks ;-)

I was wondering if you could push this patch upward in the kernel tree. It's for DMA on the ICH6_5 chipset from intel, which is found on some laptops. I'm using a Eurocom M560A.

I have been manually applying this patch since about March 2006 from kernels upward of 2.6.16. The problem was that I got this (garbage) laptop from work, immediately loaded gentoo on it, and noticed that everything from disk reads, to running X, or reading a CDROM was dreadfully slow - DMA of course ;-)

Then I did some research on the mainboard to see if there was something missing, tried running Ubuntu, and noticed that it lacked the slowness described above. I found this URL with a fairly anonymous patch and I guess up until now it hasn't sneaked into the kernel.

This patch is extremely basic, and only adds a couple of new definitions which are supported by the existing kernel code. very harmless, but it increased my disk throughput by something like 3000% :)



Reproducible: Always

Steps to Reproduce: will need a laptop with ICH6_5 / 82801FB (Mobile chipset) from intel.
2. use any gentoo kernel as is
3. hdparm -tT <your root device>

Actual Results:  
something like 3MB/sec

Expected Results:  

Check out the original patch at

It has a bit more context which could be helpful.
Comment 1 Daniel Drake (RETIRED) gentoo-dev 2007-02-24 18:40:47 UTC
I think this is deliberately excluded because it supports the newer AHCI modes so you do not need to run it in blk_dev_piix legacy mode.

Try the ATA_PIIX driver. Note that your disk will move from hda to sda.
Comment 2 Daniel Drake (RETIRED) gentoo-dev 2007-03-10 04:47:45 UTC
see comment #1
Comment 3 Christopher Friedt 2007-03-10 11:39:20 UTC
I just tested it out - what was wierd was that with the old ATA_PIIX driver, the disks would still show up as /dev/hdc ... 

After changing to the newer driver, they are now /dev/sda ...

It's working very well now

Thanks for the help ;-)