Red Hat Bugzilla – Bug 232147
Wrong DMA mode probed / Can't set mode > udma(33)
Last modified: 2007-11-30 17:11:59 EST
Description of problem: udma(133) ide disk gets wrongly detected as udma(33)
and it is not possible to set it to anything above udma(33) with hdparm.
Version-Release number of selected component (if applicable): 2.6.19-
How reproducible: always
Steps to Reproduce:
1. Boot the system
Actual results: Have to use a udma6 disk in udma2 mode, getting 27MB/s instead
Expected results: Correct detection of harddisk
Additional info: The IDE driver / Southbridge used are SIS5513 / SIS962. Same
system is detected correctly and works fine in udma6 mode with 2.6.12-
1.1378_FC3 and with Knoppix or Kanotix (2005-02) Live CDs. And yes, I'm using a
Created attachment 150003 [details]
output of hdparm -iI on FC6 and on Kanotix, dmesg
The same system with kernel 2.6.19-1.2895.fc6 does not show this issue. The
harddisk is recognized correctly and operates in udma6 mode.
Please test 2.6.20-1.2925.fc6
Just tested 2.6.20-1.2925.fc6. It shows the same problem. Only udma2 or less
Test kernels (1.2937) for this issue are at:
Please test and report back.
Tested kernel 1.2937. This time the harddisk is detected correctly as udma6. The
speed hdparm reports corresponds to this disks normal udma6 speed. It is also
possible to set the speed to any value up to udma6. It seems the issue is
resolved in this kernel. Thanks.