Bug 30801

Summary: ata UMDA problem
Product: Base System Reporter: Justin Kolb <jkolb>
Component: i386Assignee: Søren Schmidt <sos>
Status: Closed FIXED    
Severity: Affects Only Me    
Priority: Normal    
Version: Unspecified   
Hardware: Any   
OS: Any   

Description Justin Kolb 2001-09-24 23:10:01 UTC 
ASUS P5A (UDMA 33 support) + Western Digital WD136AA (UDMA 66/33 drive) + 40 PIN cable
Large number of ICRC errors followed by a drop down to PIO4 mode. UDMA mode 2 is successfully detected in the bios for the drive during a verbose boot.

Attempts to prove it was a hardware/setup problem involved many tests with combinations of the following things:
1.) Switching between AUTO DMA and forced DMA in the BIOS
2.) Setting UDMA 33 on the drive (wasn't set in earlier tests).
3.) Swapping different 40-pin cables
4.) Running full Western Digitial diagnostic suite on drive (all OK)

Note I also had this problem under 4.3 (I believe the error message has changed though).

Fix: 

Setting sysctl hw.atamodes to force PIO mode at startup, this still results in a few ICRC errors prior to the execution of this command during bootup.
Comment 1 davidx 2001-09-27 03:03:46 UTC 
It seems you have a bad cable or bad harddisk.

--
David Xu
Comment 2 Kris Kennaway freebsd_committer freebsd_triage 2001-10-05 06:56:31 UTC 
Responsible Changed
From-To: freebsd-bugs->sos

Over to the ATA maintainer
Comment 3 Søren Schmidt freebsd_committer freebsd_triage 2001-12-12 14:08:41 UTC 
State Changed
From-To: open->closed

I'm pretty certain this is due to bad hardware. Try a new cable 
if that doesn't help try a 80pin cable that helps in situations  
where noise is the killer. Also remember that an ATA cable shall 
not be longer than 18" (45cm), this is important...