Windows XP Keeps Reverting to PIO Mode

[wulf109]

It keeps changing to PIO on the controller my BR drives are on. I've tried uninstalling the driver and let windows re-install but as soon as I access it it reverts to PIO mode?

[Backpain]

Try this to start. http://techlogon.com/2011/03/28/how-to-fix-hard-drive-stuck-in-pio-mode/ Hope this helps.

[Bjs]

Windows falls back to PIO mode if it encounters a succession of errors/timeouts while transferring data. The cause can be faulty cables, ports, interference, bad hard disk, even problems of unknown cause may point to fault in psu.

Much more exhaustive guide with many causes and solution's here

[wulf109]

It appears to be my F hard drive. I was able to rip normally to my D and E hard drives,but as soon as I tried the F hard drive,I got the PIO problem. I formatted the F drive and it seems to be working normally,but it"s probably failing.

[nic2k4]

I would still replace the cable; it's always the first place to start when you get that problem.

[jman98]

XP was deliberately designed at the time so that a small number of the most trivial of drive issues, including things that no reasonable person would conclude were real "problems", would be enough to make XP fall into panic mode and switch the drive into PIO mode. The best solution to this issue involves editing the registry and setting the error counter to FFFFFFFF. There are other solutions, but my personal experience is that usually there is no real problem and it's just poor design by the programmers who wrote XP. I do get that they probably correctly realized that in case of a real problem falling into PIO mode was a good idea, but the issue I have is as I mentioned earlier, what the programmers defined as errors included trivial things that quickly caused their very low error counter to be reached and into PIO you go. Microsoft considered this to be a feature rather than a bug and it was never fixed in any SP for XP, although as far as I know they did not carry that flawed design through to Vista, Win 7 or Win 8.

[redwudz]

Reverting to PIO mode with drives using the PATA interface was not one of MS's 'better ideas'. I assume their logic was that the problematic drive would still continue to operate, even at a much slower speed. My major complaints about this reversion are in two parts. One, Windows never informed you that a drive had reverted to PIO mode. And two, there was no simple way within Windows to reset it to UDMA mode. Interestingly enough, ImgBurn can easily reset a optical drive to UDMA mode. Never knew why Windows couldn't do that.


When the reversion problem was more common, I used to post the following: (Maybe a bit dated.)

DMA reverts to PIO
The stuttering DVD drive
General description


DMA is an abbreviation for Direct Memory Access, an access method for external
devices where the data transfer is not done by the central processor, but by a
small special processor called DMA controller. It uses a procedure called cycle
stealing, where the central processor memory access cycles are delayed for very
short times to intersperse DMA controller memory access cycles. Some newer,
faster DMA modes are called UDMA (Ultra DMA).
The alternative, slow and inefficient data transfer mode is called PIO,
Programmed Input-Output, where the central processor transfers data byte for
byte or word for word. This requires many processor commands for each data word
and therefore causes a high and unwanted processor load.


Possible causes for falling back to PIO mode
The most frequent use why a CD or DVD port falls back to PIO mode is a scratched
or otherwise unreadable CD or DVD.


However, there are a few reasons why a computer may use PIO instead of DMA,
particularly when it's the hard disk port that falls back, not a CD/DVD drive
port. For example, David Duberman reported in 2005 that some Dell computers have
DMA disabled in their BIOS by default for the second hard disk. So it is a good
idea to check the BIOS settings first.


Other reasons can show up in the event log, so check this first and see if you
can find repeated Atapi errors recorded. If so, you likely have a hardware
defect. You can use the procedure described below, but your computer will
probably fall back to PIO mode again and again, until you solve the underlying
problem, which may be located inside the device, on the motherboard, or in the
IDE data cable and its connectors.


The trap
Windows contains a trap in which quite a few computers seem to get caught sooner
or later. The trap was described in a Web article whose link no longer works
(and also in another one mentioned below):
The crucial paragraphs are:
PIO mode is enabled by default in the following situations:
...
For repeated DMA errors. Windows XP will turn off DMA mode for a device after
encountering certain errors during data transfer operations. If more that six
DMA transfer timeouts occur, Windows will turn off DMA and use only PIO mode
on that device.
In this case, the user cannot turn on DMA for this device. The only option for
the user who wants to enable DMA mode is to uninstall and reinstall the device.
Windows XP downgrades the Ultra DMA transfer mode after receiving more than
six CRC errors. Whenever possible, the operating system will step down one
UDMA mode at a time (from UDMA mode 4 to UDMA mode 3, and so on).
...

Of course, drive firmware being quite complex and certainly containing
programming defects of its own, it is not all that difficult to produce such
errors. In my case a scratched DVD and later also an unreadable (overburned) CD
did the trick, got the drive to choke and Windows to disable DMA for good. Later
my hard disk hiccupped just once and also went back to PIO for good.
I had been using my laptop for DVD viewing for years, until I inserted a
borrowed and heavily scratched DVD. The player and apparently even the DVD drive
choked on it, and when I finally got the DVD to play, I found that playing was
jerky and processor load was 100%, roughly half of which was system overhead.
This indicated that the drive had reverted from the usual UDMA (Ultra Direct
Memory Access) mode 2 to PIO (Programmed Input Output) mode. No amount of
resetting or changing the relevant registry parameters from 1 (try DMA) to 2
(force DMA) helped. Stubbornly the drive kept using PIO mode, and Windows even
changed these settings back to 0 (use PIO only).
The following text will refer to the secondary IDE port because that is more
often affected, but essentially the same also holds for the primary IDE port, to
which the main hard disk is connected in most computers.
Before you begin to work on the problem, log on as Administrator or as a user
with administrator rights.


Check Your IDE Port Mode
First check what mode your secondary IDE port is currently working in. Go to
Device Manager: right-click on My Computer, select Properties, click on the
Hardware tag, click on the Device Manager button, click on the plus sign to the
left of IDE ATA/ATAPI Controller, double-click on the secondary IDE channel,
click on Extended Settings and check whether it is set to DMA when available.
Directly underneath that setting is a grey field that shows the actual working
mode of your IDE channel. You want the highest possible DMA or Ultra DMA mode
there, and you definitely don't want PIO mode.

Normally you don't have to use the registry editor for this, because the normal
settings are also available through the properties dialog for the IDE port, but
if you want to look at it anyway, the parameter for the secondary IDE port can
be found through regedit.exe at HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\Scsi\Scsi Port 1
It is named Scsi only for historic reasons. Scsi Port 0 is the primary IDE port,
to which presumably your hard disk is connected.
After trying various remedies—in vain—I found the abovementioned article and
went to work again. I uninstalled the DVD drive in Device Manager and rebooted,
but that did not help either.
So I searched for more and better information, then I went on and did the
following:


Re-enable DMA using the Registry Editor
My thanks go to my fellow MVP Alexander Grigoriev who taught me this method.
Run REGEDIT. Go to the following key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Contro l\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 other numbers can occur under certain
circumstances. You have to go through these subkeys and check the DriverDesc
value until you find the proper IDE channel.
Delete MasterIdDataChecksum or SlaveIdDataChecksum, depending on whether the
device in question 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. If so, congratulations, you've made it (at least until the next time
Windows disables DMA).
2005-10-24 – Tomáš Souček wrote, if this doesn't work, check also the dword
value MasterDeviceTimingModeAllowed, whose default value is hex 0xFFFFFFFF. If
you have a much smaller value, you can try to set it back to its default and
reboot for a test.


Alternative Method—Uninstalling the Port


1. Uninstall the secondary IDE port
To do that, open Device Manager as follows. Right-click on My Computer, select
Properties, click on the Hardware tag, click on the Device Manager button, click
on the plus sign to the left of IDE ATA/ATAPI Controller, right-click on
Secondary IDE Channel, click on Uninstall. Deactivating is not enough.
Reboot to make the changes active and permanent.
After booting Windows will automatically reinstall the IDE channel and the DVD
(or CD) drive. This Plug-n-Play process can take a little while, so give it a
minute after the boot process finishes.


2. Reactivate DMA
But this is not enough, because unfortunately Windows does not automatically
activate DMA on a DVD or CD drive. You have to tell Windows to try to use DMA
first.
For that, go to Device Manager again. Right-click on My Computer, select
Properties, click on the Hardware tag, click on the Device Manager button, click
on the plus sign to the left of IDE ATA/ATAPI Controller, double-click on the
secondary IDE channel, click on Extended Settings and change the relevant
setting from PIO only to DMA when available.
On Windows NT and 2000 you now have to reboot a second time, but Windows XP
applies the change instantly. Then you can go to the same place in Device
Manager again and check whether the device is now actually using DMA mode. If
so, all is well.


3. Driver is not intended for this platform
If you keep getting the following error message:
There is a problem installing this hardware.
IDE channelAn error occurred during the installation of the device. Driver is not
intended for this platform.


2005-03-30 – Johannes B. wrote: The reason for this error is often that Daemon
Tools or Alcohol 120% are installed. In this case the solution described below
would not work. But when you uninstall these programs and then restart Windows,
it will then install the device drivers without any further problems.
If these programs are not installed, then one possible way out is to rename
C:\WINDOWS\system32\drivers\atapi.sys (or a similar path on your computer) to
something like atapi.old.


If that's not possible, you can try it from the repair console (boot from the
Windows install CD and select the repair console).
If Windows always automatically recreates atapi.sys, you can try renaming it in
safe mode or from a command line window or you can try to rename or remove it in
the driver cache as well.


Desensitize Your Computer's IDE Channels
There's a bit more to it. The following article offers a way to reduce the
incidence of this problem, although it still doesn't solve it altogether.
IDE ATA and ATAPI Disks Use PIO Mode After Multiple Time-Out or CRC Errors Occur

http://support.microsoft.com/kb/817472/
Do read this article because it contains a useful long-term workaround. But you
have to go through the procedure described here to re-enable DMA first. Assuming
you've done that, insert the ResetErrorCountersOnSuccess registry values
mentioned in this article into both the primary and the secondary IDE port
registry keys as described.

Unfortunately this is only a half solution, because when you enter an unreadable
DVD, you will get 6 errors in a row, and the IDE channel will revert to PIO
mode, but at least when you pull out the DVD in time and then insert a good one,
the error counter will be reset and it will at least be a bit more difficult for
Windows to hobble your IDE drive.

[wulf109]

Too late it occurs to me that if I had selected Properties-Tools-Error Checking I could have fixed the PIO problem.