My Samsung DVD player reverted to PIO mode on the secondary IDE channel though when installed it was set to Ultra DMA mode 2.

I was unable to restore it back to DMA mode. It seems that Windows XP will downgrade a device after six or more CRC errors.

After checking various solutions, some people suggested editing the registry and Microsoft (see www.microsoft.com/hwdev/tech/storage/IDE-DMA.asp) recommending unistalling the device then reinstalling the device (I tried this and it did not work). I found the easiest solution was to uninstall the secondary IDE channel itself, then let Windows check for hardware changes. It will detect the secondary IDE channel and restore devices to DMA mode. All without having to reset the computer.



Hope this is of some help to users.

It seems that this is a common problem with Windows XP.

Hmm...Thanks for the tip.



Perhaps this has something to do with my CD-RW freezing my computer (e.g no mouse movement, no system activity, complete freeze) when I put a blank cd in and it's accessed by windows (which is every time, becuase windows is trying to read the CD and see it's format... )

Posted in Hardware help section. I didnt get any answers here.

Leave it on DMA mode, this is much better than PIO.

If it falls back to PIO try setting it again to DMA, if it doesn't work try my suggestion.

This happens to my HDD too, don't know why, just can't set it back. It's not possible to uninstall the main HDD while running XP, so the solution there is not valid for me. I've try to change the setting from ENABLE DMA to PIO, then switch back, but it doesn't work. My BIOS & mother board of course supports DMA and it works fine in WIN ME.



Anybody has a suggestion?

This could be caused by just reading a bad CD and then bam no more DMA

You are right.

Just another stupid 'feature' of XP.:right:

Had the same prob with my CD-RW. Suddenly noticed the computer was very slow when writing CDs. Had to open the PC and take out the drive and put it back in. Think this method should be easier

I know that this is hardcore thread resurrecting , but I would like to thank Marko & the Neowin Search Engine for solving this exact problem I had with my optical drives today

Thanks again Marko & Neowin Search Engine

Radish™

heh, I had the problem with my DVD drive not being in DMA mode, but I had to switch my dvd drive from master to slave on the secondary IDE cable in order for it to become DMA. Heh, I didn't know that the search engine even searched back a year and then some

Yep, the Search Engine is pretty good IMO

Radish™

Tried to find your post in hardware help, I remember reading about the kenwood 72x's they used a split lazer to achieve the high velocities that they ran, and there is no firmware update to make that available in XP.

Thats why your 72x only goes 16x

Kenwoods were also notoriously unstable, the ones who loved them were the ones that it worked for.

yeah, i remember that kenwood 72x, thats an old one, probably a reason why it was the only one...

Windows XP has an obnoxious relic from the old days. When a hard drive started going bad, a cyclic redundancy check error was generated and tracked by the registry. After several errors, the hard drive was noted as failing and Windows would drop to lower and lower levels of DMA until Programmed Input Output mode was the only thing left to run the aging and/or failing hard drive. Now the idjits at Microsoft have continued this practice with devices that have removeable media. Several scratched cds or dvds later, a couple of buffer overruns or whatever, and your CD/DVD runs slowly or sometimes not at all.
Here is the fix. Run regedit, navigate to the following key.

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E96A-E325-11CE-BFC1-08002BE10318}\000X

Where 000X corresponds to the various drives on your IDE bus. Likely, 0000 will be your primary hard drive,but who knows (or cares). IN each 000X key, look for "MasterIdDataCheckSum" or "SlaveIdDataCheckSum". If you see either one or both of these right-click on them and delete them. A dialog will pop up asking you to confirm the Deleteion. Click OK. Do this for each drive 000X. Restart when done. Problem solved

Another massive thread ressurection but it's some good info that would have proved useful to me about 6 months ago.

To clarify a bit more on the 000x keys.

0000 is the IDE master controller (nothing to tweak here)
0001 is the primary IDE channel
0002 is the secondary IDE channel

Nice tweak. I had bad DVD with CRC errors on it and repeatedly tried it in both of my optical drives. Now for a bit of preemptive registry editing.

yep you did the right thing. just unistall the idechannel, let windows re-recognize it aftera reboot. easiest and simpliest way to handle this problem.

Unfortunatley that method doesn't allways work. I had a hell of time fixing that issue the last time it happened to me. Removing the IDE channels caused more problems. For some reason if I do that, windows endlessly detects new hardware (the ide channels) and if I tried to let windows install the drivers it would fail with some "Drivers are not intended" error. The only way I could fix it was to install the VIA IDE miniport drivers, change modes and then remove them. I have an older abit mobo with a via 686b southbridge and amd 760 northbridge. For some reason I've only ever had trouble removing and letting windows re-detect with that combo. Newer hardware I've worked with lets me remove the channel without problems. The regedit is quick and painless.

cheers dude! this has been niggling me for a few weeks after installing a new dvdrw.

both back to UDMA again

my asus dvdrom stopping running on UDMA5 mode and reverted to pio.

the removal and installation of the controllers didnt work in this case and deleting the reg entries was the only option.