Alan Cox wrote: >> It's for draining. Let's say drive says it wanna transfer 18 bytes but >> the buffer is only 13 bytes long. If the transfer method consumes 2 >> bytes per read, it would consume 14 bytes. If the transfer method >> consumes 4 bytes per read, it would consume 16 bytes. If we drain too >> much, we risk hanging the machine. > > Do we have any actual cases where trying to drain beyond the controller > granuality is a problem ? > > Might be cleaner to sort this (and the DMA assumption of 2 byte > alignment, and possibly 16 byte for some devices/controllers) with > > dev->pio_io_size; > dev->dma_io_size; >
That could be cleaner although slightly less flexible. For example, a driver may do 32bit IOs normally but choose to do smaller size IO at the end for whatever reason. DMA alignment is host restriction so I think it belongs to ata_host if we ever need it. Do you know of any controller which require such thing? No need to add complexity when it's not necessary. Thanks. -- tejun - To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
