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Rander Wang authored
The delay function is used to calculate the difference between hw_ptr and dai dma position. I2S, DMIC and SDW will use dai dma position in shared SRAM window to calculate the delay. HDaudio will retrieve dai dma position from host mmio memory space since it doesn't support LLP counter reported by firmware. In two cases dai dma position is inaccurate for delay calculation (1) dai pipeline is started before host pipeline (2) multiple streams mixed into one. Each stream has the same dai dma position Firmware calculates correct stream_start_offset for all cases including above two. Driver subtracts stream_start_offset from dai dma position to get accurate one. Signed-off-by: Rander Wang <rander.wang@intel.com> Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com> Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com> Link: https://lore.kernel.org/r/20230202132954.26773-10-peter.ujfalusi@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>
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