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| author | Jerome Brunet <jbrunet@baylibre.com> | 2024-08-07 18:27:03 +0200 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2024-08-08 20:34:55 +0100 |
| commit | 5003d0ce5c7da3a02c0aff771f516f99731e7390 (patch) | |
| tree | 184f7ddcca1437de2fe83e700a748abdb1d40cb0 /sound/soc | |
| parent | 2f11f61f9d4d5692bcebb9d089429ee0c046e08a (diff) | |
| download | linux-stable-5003d0ce5c7da3a02c0aff771f516f99731e7390.tar.gz linux-stable-5003d0ce5c7da3a02c0aff771f516f99731e7390.tar.bz2 linux-stable-5003d0ce5c7da3a02c0aff771f516f99731e7390.zip | |
ASoC: meson: axg-fifo: fix irq scheduling issue with PREEMPT_RT
With PREEMPT_RT enabled a spinlock_t becomes a sleeping lock.
This is usually not a problem with spinlocks used in IRQ context since
IRQ handlers get threaded. However, if IRQF_ONESHOT is set, the primary
handler won't be force-threaded and runs always in hardirq context. This is
a problem because spinlock_t requires a preemptible context on PREEMPT_RT.
In this particular instance, regmap mmio uses spinlock_t to protect the
register access and IRQF_ONESHOT is set on the IRQ. In this case, it is
actually better to do everything in threaded handler and it solves the
problem with PREEMPT_RT.
Reported-by: Arseniy Krasnov <avkrasnov@salutedevices.com>
Closes: https://lore.kernel.org/linux-amlogic/20240729131652.3012327-1-avkrasnov@salutedevices.com
Suggested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Fixes: b11d26660dff ("ASoC: meson: axg-fifo: use threaded irq to check periods")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20240807162705.4024136-1-jbrunet@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'sound/soc')
| -rw-r--r-- | sound/soc/meson/axg-fifo.c | 26 |
1 files changed, 10 insertions, 16 deletions
diff --git a/sound/soc/meson/axg-fifo.c b/sound/soc/meson/axg-fifo.c index 7e6090af720b..75909196b769 100644 --- a/sound/soc/meson/axg-fifo.c +++ b/sound/soc/meson/axg-fifo.c @@ -207,25 +207,18 @@ static irqreturn_t axg_fifo_pcm_irq_block(int irq, void *dev_id) 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) - return IRQ_WAKE_THREAD; + if (status & ~FIFO_INT_COUNT_REPEAT) + dev_dbg(axg_fifo_dev(ss), "unexpected irq - STS 0x%02x\n", + status); - dev_dbg(axg_fifo_dev(ss), "unexpected irq - STS 0x%02x\n", - status); + if (status & FIFO_INT_COUNT_REPEAT) { + snd_pcm_period_elapsed(ss); + return IRQ_HANDLED; + } 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_HANDLED; -} - int axg_fifo_pcm_open(struct snd_soc_component *component, struct snd_pcm_substream *ss) { @@ -251,8 +244,9 @@ int axg_fifo_pcm_open(struct snd_soc_component *component, if (ret) return ret; - ret = request_threaded_irq(fifo->irq, axg_fifo_pcm_irq_block, - axg_fifo_pcm_irq_block_thread, + /* Use the threaded irq handler only with non-atomic links */ + ret = request_threaded_irq(fifo->irq, NULL, + axg_fifo_pcm_irq_block, IRQF_ONESHOT, dev_name(dev), ss); if (ret) return ret; |