dvdli

`pcm_mmap_get_hw_ptr` stores `errno` when the timestamp is zero, but `errno` is not set by any called functions before the zero timestamp checking. Need to replace `errno` with a specific error...

pcm_state is not listed in pcm.h, but PCM_STATE_* are listed in pcm.h. We have two ways to fix this issue. 1. Move PCM_STATE_ from pcm.h to pcm.c and mark pcm_state...