6.1 ata panic if dma enabled

[Scott Long]

Rong-En Fan wrote:
> Hi,
> 
> Recently, we upgrade a 4.11 box to 6.1-BETA2 by reinstall+newfs everything.
> After that,  we found that if hw.ata.ata_dma=1 at boot, then as soon as it
> starts fsck -p, it panics. It happens only if ad0 is setted to UDMA66 or above.
> My current solution is set hw.ata.ata_dma=0 in loader.conf and manually
> turn DMA on ad0 to UDMA33 and rest ad4~ad7 to UDMA100. In the days of
> 4.x, there is something wrong with DMA on ad0, but it will fall back to
> PIO4 automatically without problem. We have been tried to 1) change the
> cable 2) change from primary ata controller to the second, 3) upgrade to
> RELENG_6 as of March 11, but all these are failed. There is no options in
> bios to turn off DMA for the onboard ATA controller.

Please review the release notes from the 6.1-BETA2 announcement.  Fixes
went into 6.1 shortly after BETA2 was released, and are in BETA3 and BETA4.

Scott