6.6-stable review patch. If anyone has any objections, please let me know.
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From: Jerome Brunet jbrunet@baylibre.com
[ Upstream commit b11d26660dff8d7430892008616452dc8e5fb0f3 ]
With the AXG audio subsystem, there is a possible random channel shift on TDM capture, when the slot number per lane is more than 2, and there is more than one lane used.
The problem has been there since the introduction of the axg audio support but such scenario is pretty uncommon. This is why there is no loud complains about the problem.
Solving the problem require to make the links non-atomic and use the trigger() callback to start FEs and BEs in the appropriate order.
This was tried in the past and reverted because it caused the block irq to sleep while atomic. However, instead of reverting, the solution is to call snd_pcm_period_elapsed() in a non atomic context.
Use the bottom half of a threaded IRQ to do so.
Fixes: 6dc4fa179fb8 ("ASoC: meson: add axg fifo base driver") Signed-off-by: Jerome Brunet jbrunet@baylibre.com Link: https://lore.kernel.org/r/20240426152946.3078805-2-jbrunet@baylibre.com Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- sound/soc/meson/axg-fifo.c | 29 +++++++++++++++++++---------- 1 file changed, 19 insertions(+), 10 deletions(-)
diff --git a/sound/soc/meson/axg-fifo.c b/sound/soc/meson/axg-fifo.c index bde7598750064..94b169a5493b5 100644 --- a/sound/soc/meson/axg-fifo.c +++ b/sound/soc/meson/axg-fifo.c @@ -204,18 +204,26 @@ static irqreturn_t axg_fifo_pcm_irq_block(int irq, void *dev_id) unsigned int status;
regmap_read(fifo->map, FIFO_STATUS1, &status); - status = FIELD_GET(STATUS1_INT_STS, status); + axg_fifo_ack_irq(fifo, status); + + /* Use the thread to call period elapsed on nonatomic links */ if (status & FIFO_INT_COUNT_REPEAT) - snd_pcm_period_elapsed(ss); - else - dev_dbg(axg_fifo_dev(ss), "unexpected irq - STS 0x%02x\n", - status); + return IRQ_WAKE_THREAD;
- /* Ack irqs */ - axg_fifo_ack_irq(fifo, status); + dev_dbg(axg_fifo_dev(ss), "unexpected irq - STS 0x%02x\n", + status); + + return IRQ_NONE; +} + +static irqreturn_t axg_fifo_pcm_irq_block_thread(int irq, void *dev_id) +{ + struct snd_pcm_substream *ss = dev_id; + + snd_pcm_period_elapsed(ss);
- return IRQ_RETVAL(status); + return IRQ_HANDLED; }
int axg_fifo_pcm_open(struct snd_soc_component *component, @@ -243,8 +251,9 @@ int axg_fifo_pcm_open(struct snd_soc_component *component, if (ret) return ret;
- ret = request_irq(fifo->irq, axg_fifo_pcm_irq_block, 0, - dev_name(dev), ss); + ret = request_threaded_irq(fifo->irq, axg_fifo_pcm_irq_block, + axg_fifo_pcm_irq_block_thread, + IRQF_ONESHOT, dev_name(dev), ss); if (ret) return ret;