New: dma not enabled for IDE hard drives

http://bugme.osdl.org/show_bug.cgi?id=530

Summary: dma not enabled for IDE hard drives
Kernel Version: 2.5.66
Status: NEW
Severity: normal
Owner: [email protected]
Submitter: [email protected]

Distribution: Debian/Sid

Hardware Environment: dual 2.4Ghz Xeon, SE7500CW2 MB, all Intel
Promise PDC20267 ATA-100 ide channels in non-RAID mode

Software Environment: testing with hdparm 5.2-1 of Debian/Sid

Problem Description:

I have similar .config settings for both the 2.4.20 and the 2.5.66 kernels with the identical machine. Under 2.4.20, I do get dma enabled and see good performance (Mb/s) from the hard disk I/O.

However, under the 2.5.66 kernel, dma is not enabled and the performance of the hard drives is poor (~2-3 Mb/s under 2.4.20 versus ~30 Mb/s under 2.5.66). The "hdparm -I /dev/hda" command confirms that dma is not enabled under 2.5.66, but is under 2.4.20.

Steps to reproduce: