On 28/05/2021 17:15, Leo Yan wrote:

The callback cs_etm_find_snapshot() is invoked for snapshot mode, its
main purpose is to find the correct AUX trace data and returns "head"
and "old" (we can call "old" as "old head") to the caller, the caller
__auxtrace_mmap__read() uses these two pointers to decide the AUX trace
data size.

cs_etm_find_snapshot() should be removed with below reasons:

Hi Leo,

I came across this other comment in coresight-tmc-etr.c that should probably
be fixed up if we remove cs_etm_find_snapshot(). The same is duplicated in a
few other files:

	/*
	 * In snapshot mode we simply increment the head by the number of byte
	 * that were written.  User space function  cs_etm_find_snapshot() will
	 * figure out how many bytes to get from the AUX buffer based on the
	 * position of the head.
	 */
	if (etr_perf->snapshot)
		handle->head += size;

I'm still reviewing patch 1 and 2 as well.

James


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