> The general idea: A daemon running in user space monitors input data > from an accelerometer. When the daemon detects a critical condition, That sounds like a non starter. What if the box is busy, what if the daemon or something you touch needs memory and causes paging ? Given the accelerometer data should be very simple doesn't it actually make sense in this specific case to put the logic (not thresholds) in kernel space. > state. To this end, the kernel has to issue an idle immediate command > with unload feature and stop the block layer queue afterwards. Once the Yep. Pity the worst case completion time for an IDE I/O is 60 seconds or so. > 1. Who is to be in charge for the shock protection application? Should > userspace speak to libata / ide directly (through sysfs) and the low I think it has to be kernel side for speed, and because you will need to issue idle immediate while a command sequence is active which is *extremely* hairy as you have to recover from the mess and restart the relevant I/O. Plus you may need controller specific knowledge on issuing it (and changes to libata). > 2. Depending on the answer to the previous question, by what mechanism > should block layer and lld interact? Special requests, queue hooks or > something in some way similar to power management functions (once > suggested by James Bottomley)? Idle immediate seem to simply fit the queue model, it happens in *parallel* to I/O events and is special in all sorts of ways. > 3. What is the preferred way to pass device specific configuration > options to libata (preferrably at runtime, i.e., after module > loading)? sysfs - 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
