On Thu, Jan 14, 2010 at 10:48:33AM +0100, Magnus Christensson wrote:
Hi,
The recently introduced DMA support in Seabios fails to work on Virtutech Simics. The reason is that DMA has not enabled in the disk. I'm trying to figure out if this is a bug in my setup of Simics, or a bug in Seabios. Shouldn't Seabios enable DMA in the disk through the SET FEATURES command?
My read of the spec was that the set_features command was only needed to specify which dma mode was desired, and that the drive would default into mwdma mode by default. I'll take a closer look through the spec this weekend. The current code does seem to work with the real drives I have.
In either case though, we probably should have a CONFIG_ATA_DMA define to manually disable that support.
-Kevin