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Add a new FAQ entry explaining UDMA ICRC errors.

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PR:		41643
Submitted by:	David Sieborger <drs@rucus.ru/ac/za>
This commit is contained in:
Tom Rhodes 2002-12-20 00:54:47 +00:00
parent 85d657d53b
commit 39a6e677fb
Notes: svn2git 2020-12-08 03:00:23 +00:00 
svn path=/head/; revision=15392
1 changed files with 33 additions and 0 deletions
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en_US.ISO8859-1/books/faq/book.sgml
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@ -4378,6 +4378,39 @@ kern.timecounter.hardware: TSC -&gt; i8254</screen>
and connections.</para> and connections.</para>
</answer> </answer>
</qandaentry> </qandaentry>
<qandaentry>
<question id="udma-icrc">
<para>What are <quote>UDMA ICRC</quote> errors, and how do I
fix them?</para>
</question>
<answer>
<para>The &man.ata.4; driver reports <quote>UDMA ICRC</quote>
errors when a DMA transfer to or from a drive is corrupted.
The driver will retry the operation a few times. Should
the retries fail, it will switch from DMA to the slower PIO
mode of communication with the device.</para>
<para>The problem can be caused by many factors, although
perhaps the most common cause is faulty or incorrect
cabling. Check that the ATA cables are undamaged and rated
for the Ultra DMA mode in use. If you're using removable
drive trays, they must also be compatible. Be sure that
all connections are making good contact. Problems have
also been noticed when an old drive is installed on the
same ATA channel as an Ultra DMA 66 (or faster) drive.
Lastly, these errors can indicate that the drive is
failing. Most drive vendors provide testing software for
their drives, so test your drive, and, if necessary, back
up your data and replace it.</para>
<para>The &man.atacontrol.8; utility can be used to show and
select the DMA or PIO modes used for each ATA device. In
particular, <command>atacontrol mode
<replaceable>channel</replaceable></command> will show the
modes in use on a particular ATA channel, where the primary
channel is numbered 0, and so on.</para>
</answer>
</qandaentry>
</qandaset> </qandaset>
</chapter> </chapter>