diff options
Diffstat (limited to 'sound/firewire/amdtp-stream.c')
| -rw-r--r-- | sound/firewire/amdtp-stream.c | 51 |
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 |