intel: ssp: drain RX fifo when starting #7577
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kv2019i
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dbaluta,
lbetlej,
lgirdwood,
mmaka1 and
plbossart
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@plbossart @ujfalusi I also tried option to disable RSRE (Receive Service Request Enable) when stopping capture, but I could not get this to work. Then I found Pierre your commit "intel: ssp: handle TSRE and RSRE along with SSE" 441b438 . That states RSRE should be set before SSE and if we followed that, we can't really disable RSRE when capture is stopped but playback continues. So that leaves us with the current fix in this PR. |
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FYI @bardliao who worked on this area with the ES_BCLK feature. |
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If DMA is active, do not read data directly from the SSP RX fifo. Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
If DMA transaction is ongoing when RX is enabled, this can lead to stuck communication between DMA and SSP (DMA service request not seen by the DMA). To avoid this, flush the RX fifo before enabling SSP RX. Link: thesofproject#7548 Suggested-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com> Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
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| uint64_t sample_ticks = clock_ticks_per_sample(PLATFORM_DEFAULT_CLOCK, | ||
| ssp->params.fsync_rate); | ||
| uint32_t retry = SSP_RX_FLUSH_RETRY_MAX; | ||
| bool direct_reads = ssp->state[DAI_DIR_CAPTURE] <= COMP_STATE_PREPARE; |
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how about COMP_STATE_PAUSED? it is not active, and seems will not read with this state.
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@btian1 That's a good question. Earlier version of the patch broke PAUSE, so I did spend some time looking at this. Curiously, ssp_pause does not stop the hardware and it based on tests, this is not needed after pause. I can't fully explain why this is the case (and DMA is stopped on pause).
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the other patch fixes the pause by yanking the FIFO before resume (which is a start operation), it is really strange to be honest, but w/o the FIFO drain patch I had broken pause/resume and I think @kv2019i had a working one on his (identical) setup.
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Failing CI checks do not test the configuration this PR changes. Proceeding with merge. Thanks to all reviewers! |
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Mainline version of #7564
Link: #7548