atacontrol mode D PIO4 persist across reboots

[Manolis Kiagias]

Philip M. Gollucci wrote:
> /var/run/dmesg.boot
> ad2: 28667MB <SAMSUNG SV3002H PV100-11> at ata1-master UDMA33
> ad2: FAILURE - READ_DMA timed out LBA=58711965
> ad2: TIMEOUT - READ_DMA retrying (1 retry left) LBA=0
> ad2: FAILURE - READ_DMA timed out LBA=58711951
> ad2: TIMEOUT - READ_DMA retrying (0 retries left) LBA=0
> ad2: FAILURE - READ_DMA timed out LBA=58711964
> ad2: FAILURE - READ_DMA timed out LBA=0
> ....
> 10-30 minutes later, it finally gets through the boot.
>
> /etc/fstab:
> /dev/ad2s1 /X ufs rw 2 2
>
> the problem here is the device needs to be PIO4
>
> $ atacontrol mode ad2 PIO4
> current mode = PIO4
>
> My problem is how do I get this to persist across reboot ?
>
>
Have a look at man 4 ata
Your answer is probably:

  hw.ata.ata_dma=0

in /boot/loader.conf

Are you sure it is not a faulty (or failing) disk though? This size / 
age drive should have no problem running in DMA mode.