DVD suddenly PIO (no DMA)

[Lars-Erik Østerud]

Suddenly my Plextor 716A got terrible problems and slow writing.

After some checking a saw that the max DMA mode (in Hardware control
panel) is PIO and not DMA, even if "DMA if available" is set ON.

And I cannot change it. DMA is on in BIOS and max DMA is detected
right in BIOS. What can cause this? How do I fix this in WinXP?

 

[Nightowl]

Suddenly my Plextor 716A got terrible problems and slow writing.

After some checking a saw that the max DMA mode (in Hardware control
panel) is PIO and not DMA, even if "DMA if available" is set ON.

And I cannot change it. DMA is on in BIOS and max DMA is detected
right in BIOS. What can cause this? How do I fix this in WinXP?

Hi Lars-Erik

Windows can switch to PIO mode on a drive after a certain number of
time-out or CRC errors. Here's a quick method that should fix it for
you, originally from MVP Alexander Grigoriev.

Run Regedit and got to to the following key:

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

It has subkeys like 0000, 0001, 0002, etc. Normally 0001 is the primary
IDE channel, 0002 the secondary, but this isn't always the case (on my
system for some reason 0002 is the primary channel). You need to go
through these subkeys and check the DriverDesc value until you find the
correct IDE channel.

As always, it's a good idea to export the key data as a .reg file before
changing the registry, just in case you should need to restore it. Then:

Delete MasterIdDataChecksum or SlaveIdDataChecksum, depending on whether
the problem drive is attached as master or slave, but it can't actually
hurt to delete both. Reboot. The drive DMA capabilities will be
redetected.

Open Device Manager again and check whether the device is now actually
using DMA mode.

Hope this helps Let us know how it goes!

 

[Lars-Erik Østerud]

Windows can switch to PIO mode on a drive after a certain number of
time-out or CRC errors. Here's a quick method that should fix it for
you, originally from MVP Alexander Grigoriev.

Aha, so the DVD+RW I tried to copy with read errors could have caused
this? But shouldn't it revert back? If not, what an idiotic function

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

It has subkeys like 0000, 0001, 0002, etc. Normally 0001 is the primary
IDE channel, 0002 the secondary, but this isn't always the case (on my

I only have secondary (HDD is on S-ATA) and only device is DVD+RW so
I'll find it.

Delete MasterIdDataChecksum or SlaveIdDataChecksum, depending on whether
the problem drive is attached as master or slave, but it can't actually
hurt to delete both. Reboot. The drive DMA capabilities will be

I'll try. Will it do the same to delete the drive for "Device manager"
and auto-detect again, or will XP save the settings for the drive?

It should be an easier way to reset this (for non-tech people).
For me it's no problem hacking the registry, but for others...

 

[Jim]

Suddenly my Plextor 716A got terrible problems and slow writing.

After some checking a saw that the max DMA mode (in Hardware control
panel) is PIO and not DMA, even if "DMA if available" is set ON.

And I cannot change it. DMA is on in BIOS and max DMA is detected
right in BIOS. What can cause this? How do I fix this in WinXP?

When an excessive number of errors occur, XP reverts the driver to PIO mode.
This setting sticks in the driver.
If I remember correctly, it will be necessary to remove the driver and
reboot. When XP enumerates the
computer, it copies a fresh copy from the \i386 folder.
The theory behind this action seems to be that this is an instance where
some human must take charge and fix
the problem.
You job would be to determine why the drive is getting too many errors.
Jim

 

[Lars-Erik Østerud]

You job would be to determine why the drive is getting too many errors.

I see the logic if there are transfer errors between the drive and the
controller. But it did this when I tried to copy a disk with errors.
XP should be able to separate between communication errors and disk
read errors (setting the transfer speed on the controller down will
NOT help on disk read error, so why do that in those cases ?!?!?!?)

 

[M8RIX]

There is a .vbs file that fixes this issue quite easily as well as alot of
detailed info on how and why this happens. You can find the vbs here~~~>
http://winhlp.com/node/10

I have used it personally and it works very well.