On Wed, 27 Jun 2007, Jeff Garzik wrote: > > Such would be a diagnostic that would trigger on valid SCSI commands, when the > user is doing nothing wrong and the system can indeed complete the command > just fine. Additionally, this is moving us in the direction of what the IDE > driver has apparently been doing. Indeed. At least the IDE CD-ROM driver does if ((rq->data_len & 15) || (addr & mask)) info->dma = 0; where the "mask" is the dma_alignment mask. So it requires the length to be a multiple of 16, and also requires a certain alignment of the data (which defaults to 32 bytes for some reason I cannot for the life of me remember). The generic BIO layer does that DMA alignment check too when mapping user pages. Linus - To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
