problems with DMA

["Mat" <matteo@spark.homeunix.org>]

Hi fellows!
Since I installed a secondary UDMA drive (hdd) as a slave of another UDMA drive 
(hdc) on an old (that doesn't support UDMA) P75, at boot time I get the error below .
If the same drive (hdd) is slave of a not-UDMA HD and the other (hdc) is the 
standalone master of its own channel (or is not installed), all is working fine. Someone 
knows why this happens?
There's a way to disable DMA in the kernel (without recompiling), so I can avoid this 
annoying message (and the waste of time), or to have DMA working? (using a rc*.d 
script with hdparm parameters doesn't work, because partition check comes first)

Many many thanks to all who will help.
Mat

Jan  8 10:57:04 spark kernel: Partition check:
Jan  8 10:57:04 spark kernel:  hda: hda1 hda2
Jan  8 10:57:04 spark kernel:  hdc: [PTBL] [2481/255/63] hdc1 hdc2 < hdc5 hdc6 hdc7 
>
Jan  8 10:57:04 spark kernel:  hdd:hdd: timeout waiting for DMA
Jan  8 10:57:04 spark kernel: hdd: irq timeout: status=0x58 { DriveReady 
SeekComplete DataRequest }
Jan  8 10:57:04 spark kernel: hdd: timeout waiting for DMA
Jan  8 10:57:04 spark kernel: hdd: irq timeout: status=0x58 { DriveReady 
SeekComplete DataRequest }
Jan  8 10:57:04 spark kernel: hdd: timeout waiting for DMA
Jan  8 10:57:04 spark kernel: hdd: irq timeout: status=0x58 { DriveReady 
SeekComplete DataRequest }
Jan  8 10:57:04 spark kernel: hdd: timeout waiting for DMA
Jan  8 10:57:04 spark kernel: hdd: irq timeout: status=0x58 { DriveReady 
SeekComplete DataRequest }
Jan  8 10:57:04 spark kernel: hdc: DMA disabled
Jan  8 10:57:04 spark kernel: hdd: DMA disabled
Jan  8 10:57:04 spark kernel: ide1: reset: success
Jan  8 10:57:04 spark kernel:  [PTBL] [784/255/63] hdd1