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Diffstat (limited to 'sound/firewire/amdtp-stream.c')
-rw-r--r--sound/firewire/amdtp-stream.c51
1 files changed, 30 insertions, 21 deletions
diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c
index 7486eec4d958..23677b805b05 100644
--- a/sound/firewire/amdtp-stream.c
+++ b/sound/firewire/amdtp-stream.c
@@ -1099,35 +1099,44 @@ err_unlock:
}
/**
- * amdtp_stream_pcm_pointer - get the PCM buffer position
+ * amdtp_domain_stream_pcm_pointer - get the PCM buffer position
+ * @d: the AMDTP domain.
* @s: the AMDTP stream that transports the PCM data
*
* Returns the current buffer position, in frames.
*/
-unsigned long amdtp_stream_pcm_pointer(struct amdtp_stream *s)
+unsigned long amdtp_domain_stream_pcm_pointer(struct amdtp_domain *d,
+ struct amdtp_stream *s)
{
- /*
- * This function is called in software IRQ context of period_tasklet or
- * process context.
- *
- * When the software IRQ context was scheduled by software IRQ context
- * of IR/IT contexts, queued packets were already handled. Therefore,
- * no need to flush the queue in buffer anymore.
- *
- * When the process context reach here, some packets will be already
- * queued in the buffer. These packets should be handled immediately
- * to keep better granularity of PCM pointer.
- *
- * Later, the process context will sometimes schedules software IRQ
- * context of the period_tasklet. Then, no need to flush the queue by
- * the same reason as described for IR/IT contexts.
- */
- if (!in_interrupt() && amdtp_stream_running(s))
- fw_iso_context_flush_completions(s->context);
+ struct amdtp_stream *irq_target = d->irq_target;
+
+ if (irq_target && amdtp_stream_running(irq_target)) {
+ // This function is called in software IRQ context of
+ // period_tasklet or process context.
+ //
+ // When the software IRQ context was scheduled by software IRQ
+ // context of IT contexts, queued packets were already handled.
+ // Therefore, no need to flush the queue in buffer furthermore.
+ //
+ // When the process context reach here, some packets will be
+ // already queued in the buffer. These packets should be handled
+ // immediately to keep better granularity of PCM pointer.
+ //
+ // Later, the process context will sometimes schedules software
+ // IRQ context of the period_tasklet. Then, no need to flush the
+ // queue by the same reason as described in the above
+ if (!in_interrupt()) {
+ // Queued packet should be processed without any kernel
+ // preemption to keep latency against bus cycle.
+ preempt_disable();
+ fw_iso_context_flush_completions(irq_target->context);
+ preempt_enable();
+ }
+ }
return READ_ONCE(s->pcm_buffer_pointer);
}
-EXPORT_SYMBOL(amdtp_stream_pcm_pointer);
+EXPORT_SYMBOL_GPL(amdtp_domain_stream_pcm_pointer);
/**
* amdtp_stream_pcm_ack - acknowledge queued PCM frames