Takashi Sakamoto wrote:
Some devices arrange the position of PCM/MIDI data channel in AMDTP packet. This commit allows drivers to set channel mapping.
To be simple, the mapping table is an array with fixed length. Then the number of channels for PCM is restricted by 64 channels.
+++ b/sound/firewire/amdtp.c @@ -351,22 +358,20 @@ static void amdtp_write_s32(struct amdtp_stream *s, __be32 *buffer, unsigned int frames) { struct snd_pcm_runtime *runtime = pcm->runtime;
- unsigned int channels, remaining_frames, frame_step, i, c;
- unsigned int remaining_frames, i, c; const u32 *src;
- channels = s->pcm_channels;
This change is not necessary. I used a separate local variable deliberately to allow the compiler to recognize that it cannot be aliased with the buffer contents.
@@ -403,29 +406,29 @@ static void amdtp_write_s32_dualwire(struct amdtp_stream *s, for (i = 0; i < frames; ++i) { for (c = 0; c < channels; ++c) {
buffer[s->pcm_positions[c] * 2] =cpu_to_be32((*src >> 8) | 0x40000000); src++;buffer += 1;buffer[s->pcm_positions[c] * 2] =cpu_to_be32((*src >> 8) | 0x40000000); src++;buffer += s->data_block_quadlets - 1;if (--remaining_frames == 0)src = (void *)runtime->dma_area;
AFAICS the dual-wire format could be handled easier by setting pcm_positions[] in the dice driver.
Regards, Clemens