Prev: [PATCH] JFS: Free sbi memory in error path
Next: perf-probe updates - data-structure support improvements, etc.
From: Krishna Gopal on 12 Apr 2010 13:10 Would there be any issues for optimization purpose I do a mmap to a peripheral register to directly access it from userspace ? This is considering the peripheral already has a Kernel driver through which you can set the register bit. Basically I want to avoid the additional context switch on entering the Kernel to set that one bit in the Peripheral register. I request you to please share your thoughts. Best regards, Krishna -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Clemens Ladisch on 13 Apr 2010 07:40
Krishna Gopal wrote: > Would there be any issues for optimization purpose I do a mmap to a > peripheral register to directly access it from userspace ? This means that userspace could access any register in the same page. Usually this is done only with read-only pages and with devices that are designed for this so that all accessible registers are 'safe'. Regards, Clemens -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |