From ca81090a00e3e7152fe1f3d7398f11d57919428e Mon Sep 17 00:00:00 2001 From: Clemens Ladisch Date: Mon, 2 May 2005 08:55:54 +0200 Subject: [PATCH] [ALSA] usb-audio - use only one packet in synchronization feedback URBs USB generic driver Do not use more than one packet in synchronization feedback URBs because it would be pointless to send or receive more than one value at the same time. Signed-off-by: Clemens Ladisch --- sound/usb/usbaudio.c | 93 ++++++++++++++++++---------------------------------- 1 file changed, 31 insertions(+), 62 deletions(-) diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c index e1a648d..a5e97d0 100644 --- a/sound/usb/usbaudio.c +++ b/sound/usb/usbaudio.c @@ -177,7 +177,7 @@ struct snd_usb_substream { unsigned int nurbs; /* # urbs */ snd_urb_ctx_t dataurb[MAX_URBS]; /* data urb table */ snd_urb_ctx_t syncurb[SYNC_URBS]; /* sync urb table */ - char syncbuf[SYNC_URBS * MAX_PACKS * 4]; /* sync buffer; it's so small - let's get static */ + char syncbuf[SYNC_URBS * 4]; /* sync buffer; it's so small - let's get static */ char *tmpbuf; /* temporary buffer for playback */ u64 formats; /* format bitmasks (all or'ed) */ @@ -251,17 +251,13 @@ static int prepare_capture_sync_urb(snd_usb_substream_t *subs, { unsigned char *cp = urb->transfer_buffer; snd_urb_ctx_t *ctx = (snd_urb_ctx_t *)urb->context; - int i, offs; - urb->number_of_packets = ctx->packets; urb->dev = ctx->subs->dev; /* we need to set this at each time */ - for (i = offs = 0; i < urb->number_of_packets; i++, offs += 4, cp += 4) { - urb->iso_frame_desc[i].length = 3; - urb->iso_frame_desc[i].offset = offs; - cp[0] = subs->freqn >> 2; - cp[1] = subs->freqn >> 10; - cp[2] = subs->freqn >> 18; - } + urb->iso_frame_desc[0].length = 3; + urb->iso_frame_desc[0].offset = 0; + cp[0] = subs->freqn >> 2; + cp[1] = subs->freqn >> 10; + cp[2] = subs->freqn >> 18; return 0; } @@ -277,18 +273,14 @@ static int prepare_capture_sync_urb_hs(snd_usb_substream_t *subs, { unsigned char *cp = urb->transfer_buffer; snd_urb_ctx_t *ctx = (snd_urb_ctx_t *)urb->context; - int i, offs; - urb->number_of_packets = ctx->packets; urb->dev = ctx->subs->dev; /* we need to set this at each time */ - for (i = offs = 0; i < urb->number_of_packets; i++, offs += 4, cp += 4) { - urb->iso_frame_desc[i].length = 4; - urb->iso_frame_desc[i].offset = offs; - cp[0] = subs->freqn; - cp[1] = subs->freqn >> 8; - cp[2] = subs->freqn >> 16; - cp[3] = subs->freqn >> 24; - } + urb->iso_frame_desc[0].length = 4; + urb->iso_frame_desc[0].offset = 0; + cp[0] = subs->freqn; + cp[1] = subs->freqn >> 8; + cp[2] = subs->freqn >> 16; + cp[3] = subs->freqn >> 24; return 0; } @@ -418,15 +410,11 @@ static int prepare_playback_sync_urb(snd_usb_substream_t *subs, snd_pcm_runtime_t *runtime, struct urb *urb) { - int i, offs; snd_urb_ctx_t *ctx = (snd_urb_ctx_t *)urb->context; - urb->number_of_packets = ctx->packets; urb->dev = ctx->subs->dev; /* we need to set this at each time */ - for (i = offs = 0; i < urb->number_of_packets; i++, offs += 4) { - urb->iso_frame_desc[i].length = 3; - urb->iso_frame_desc[i].offset = offs; - } + urb->iso_frame_desc[0].length = 3; + urb->iso_frame_desc[0].offset = 0; return 0; } @@ -440,15 +428,11 @@ static int prepare_playback_sync_urb_hs(snd_usb_substream_t *subs, snd_pcm_runtime_t *runtime, struct urb *urb) { - int i, offs; snd_urb_ctx_t *ctx = (snd_urb_ctx_t *)urb->context; - urb->number_of_packets = ctx->packets; urb->dev = ctx->subs->dev; /* we need to set this at each time */ - for (i = offs = 0; i < urb->number_of_packets; i++, offs += 4) { - urb->iso_frame_desc[i].length = 4; - urb->iso_frame_desc[i].offset = offs; - } + urb->iso_frame_desc[0].length = 4; + urb->iso_frame_desc[0].offset = 0; return 0; } @@ -462,17 +446,12 @@ static int retire_playback_sync_urb(snd_usb_substream_t *subs, snd_pcm_runtime_t *runtime, struct urb *urb) { - int i; - unsigned int f, found; - unsigned char *cp = urb->transfer_buffer; + unsigned int f; unsigned long flags; - found = 0; - for (i = 0; i < urb->number_of_packets; i++, cp += 4) { - if (urb->iso_frame_desc[i].status || - urb->iso_frame_desc[i].actual_length < 3) - continue; - f = combine_triple(cp) << 2; + if (urb->iso_frame_desc[0].status == 0 && + urb->iso_frame_desc[0].actual_length == 3) { + f = combine_triple((u8*)urb->transfer_buffer) << 2; #if 0 if (f < subs->freqn - (subs->freqn>>3) || f > subs->freqmax) { snd_printd(KERN_WARNING "requested frequency %d (%u,%03uHz) out of range (current nominal %d (%u,%03uHz))\n", @@ -481,11 +460,8 @@ static int retire_playback_sync_urb(snd_usb_substream_t *subs, continue; } #endif - found = f; - } - if (found) { spin_lock_irqsave(&subs->lock, flags); - subs->freqm = found; + subs->freqm = f; spin_unlock_irqrestore(&subs->lock, flags); } @@ -502,21 +478,14 @@ static int retire_playback_sync_urb_hs(snd_usb_substream_t *subs, snd_pcm_runtime_t *runtime, struct urb *urb) { - int i; - unsigned int found; - unsigned char *cp = urb->transfer_buffer; + unsigned int f; unsigned long flags; - found = 0; - for (i = 0; i < urb->number_of_packets; i++, cp += 4) { - if (urb->iso_frame_desc[i].status || - urb->iso_frame_desc[i].actual_length < 4) - continue; - found = combine_quad(cp) & 0x0fffffff; - } - if (found) { + if (urb->iso_frame_desc[0].status == 0 && + urb->iso_frame_desc[0].actual_length == 4) { + f = combine_quad((u8*)urb->transfer_buffer) & 0x0fffffff; spin_lock_irqsave(&subs->lock, flags); - subs->freqm = found; + subs->freqm = f; spin_unlock_irqrestore(&subs->lock, flags); } @@ -1039,18 +1008,18 @@ static int init_substream_urbs(snd_usb_substream_t *subs, unsigned int period_by snd_urb_ctx_t *u = &subs->syncurb[i]; u->index = i; u->subs = subs; - u->packets = nrpacks; - u->urb = usb_alloc_urb(u->packets, GFP_KERNEL); + u->packets = 1; + u->urb = usb_alloc_urb(1, GFP_KERNEL); if (! u->urb) { release_substream_urbs(subs, 0); return -ENOMEM; } - u->urb->transfer_buffer = subs->syncbuf + i * nrpacks * 4; - u->urb->transfer_buffer_length = nrpacks * 4; + u->urb->transfer_buffer = subs->syncbuf + i * 4; + u->urb->transfer_buffer_length = 4; u->urb->dev = subs->dev; u->urb->pipe = subs->syncpipe; u->urb->transfer_flags = URB_ISO_ASAP; - u->urb->number_of_packets = u->packets; + u->urb->number_of_packets = 1; u->urb->interval = 1 << subs->syncinterval; u->urb->context = u; u->urb->complete = snd_usb_complete_callback(snd_complete_sync_urb); -- 2.7.4