Bug 67539

Summary: /proc/ide/piix does not display correct DMA mode
Product: [Retired] Red Hat Linux Reporter: Roderick Constance <rconstance>
Component: kernelAssignee: Arjan van de Ven <arjanv>
Status: CLOSED CURRENTRELEASE QA Contact: Brian Brock <bbrock>
Severity: medium Docs Contact:
Priority: medium    
Version: 7.3   
Target Milestone: ---   
Target Release: ---   
Hardware: i686   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2004-09-30 15:39:42 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Attachments:
Description Flags
steps to reproduce
none
steps to reproduce: reversion to udma5 performance hit none

Description Roderick Constance 2002-06-26 23:32:56 UTC
Description of Problem:

On a Tyan S2720-based system (Intel E7500 chipset), /proc/ide/piix does not show
the correct DMA mode.  'hdparm -iv /dev/hda' and /proc/ide/hda/settings will
show UDMA5 while /proc/ide/piix will show UDMA3.  Once I force the DMA mode
using 'hdparm -X69 /dev/hda', then will piix show UDMA5.  I benchmarked the
system with and without forcing using hdparm, and both results show UDMA5
performance

Version-Release number of selected component (if applicable):
RedHat 7.3 Errata (2.4.18-5smp)

How Reproducible:
Always

Steps to Reproduce:
1. see attachment
2 [details]. 
3. 

Actual Results:
see attachment

Expected Results:
expect to see /proc/ide/piix to display UDMA5 without forcing using hdparm.

Additional Information:

Comment 1 Roderick Constance 2002-06-26 23:35:44 UTC
Created attachment 62784 [details]
steps to reproduce

Comment 2 Roderick Constance 2002-07-23 23:17:33 UTC
I've also been experiencing a performance hit when reverting back to udma5 mode.
 Starting in udma5 mode will produce expected performance.  Changing to a slower
udma setting will produce expectedly slower performance.  But when changing back
to udma5, the performance is as slow as the sub-udma5 tests.

Comment 3 Roderick Constance 2002-07-23 23:20:32 UTC
Created attachment 66684 [details]
steps to reproduce: reversion to udma5 performance hit

Comment 4 Bugzilla owner 2004-09-30 15:39:42 UTC
Thanks for the bug report. However, Red Hat no longer maintains this version of
the product. Please upgrade to the latest version and open a new bug if the problem
persists.

The Fedora Legacy project (http://fedoralegacy.org/) maintains some older releases, 
and if you believe this bug is interesting to them, please report the problem in
the bug tracker at: http://bugzilla.fedora.us/