> i was going through the "understanding linux kernel" and i was wondering that > how the kernel or the device driver choose the method for IO. > is there any rule of thumb by which it decides whether it should go for DMA > or programmed IO. > > i m pretty confused .. please help me out ? alot depends greatly on the hardware and how much data has to be transfered. But quite often if DMA fails for some reson it will try to fall back to PIO something working slowly can be better than not working at all. -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
