[4/9,v2] ALSA: usb-audio: use usb_fill_int_urb()
From: Takashi Iwai <hidden>
Date: 2018-06-20 13:21:49
Also in:
alsa-devel
On Wed, 20 Jun 2018 11:38:27 +0200, Sebastian Andrzej Siewior wrote:
Using usb_fill_int_urb() helps to find code which initializes an URB. A grep for members of the struct (like ->complete) reveal lots of other things, too. data_ep_set_params() additionally sets urb->transfer_buffer_length which was not the case earlier. usb_fill_int_urb() ensures that syncinterval is within the allowed range on HS/SS. The interval value seems to come from snd_usb_parse_datainterval() which is bInterval - 1 and only in the rage 1 … 4. So in order to keep the magic working I pass datainterval + 1.
This needs more explanation. By this conversion, the interval computation becomes really tricky. There are two interval calculations. The first one is fp->datainterval and it's from snd_usb_parse_datainterval() as you mentioned. And a tricky part is that fp->datainterval is 0 on FULL_SPEED. Casually, fp->datainterval+1 will be translated to the correct value since (0 + 1) == (1 << 0). OTOH, for the sync EP, it's taken from ep->syncinterval, which is set in snd_usb_add_endpoint(). Luckily, again, ep->syncinterval + 1 works for FULL_SPEED as well, as (1 + 1) == (1 << 1). thanks, Takashi
quoted hunk
Cc: Jaroslav Kysela <perex@perex.cz> Cc: Takashi Iwai <tiwai@suse.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- v1…v2: description changes (spelling + usb_fill_int_urb() ensures "syncinterval" not data_ep_set_params()) sound/usb/endpoint.c | 24 ++++++++++-------------- 1 file changed, 10 insertions(+), 14 deletions(-)diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c index c90607ebe155..bbc02db5b417 100644 --- a/sound/usb/endpoint.c +++ b/sound/usb/endpoint.c@@ -772,6 +772,8 @@ static int data_ep_set_params(struct snd_usb_endpoint *ep, /* allocate and initialize data urbs */ for (i = 0; i < ep->nurbs; i++) { struct snd_urb_ctx *u = &ep->urb[i]; + void *buf; + u->index = i; u->ep = ep; u->packets = urb_packs;@@ -783,16 +785,13 @@ static int data_ep_set_params(struct snd_usb_endpoint *ep, if (!u->urb) goto out_of_memory; - u->urb->transfer_buffer = - usb_alloc_coherent(ep->chip->dev, u->buffer_size, - GFP_KERNEL, &u->urb->transfer_dma); - if (!u->urb->transfer_buffer) + buf = usb_alloc_coherent(ep->chip->dev, u->buffer_size, + GFP_KERNEL, &u->urb->transfer_dma); + if (!buf) goto out_of_memory; - u->urb->pipe = ep->pipe; + usb_fill_int_urb(u->urb, NULL, ep->pipe, buf, u->buffer_size, + snd_complete_urb, u, ep->datainterval + 1); u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP; - u->urb->interval = 1 << ep->datainterval; - u->urb->context = u; - u->urb->complete = snd_complete_urb; INIT_LIST_HEAD(&u->ready_list); }@@ -823,15 +822,12 @@ static int sync_ep_set_params(struct snd_usb_endpoint *ep) u->urb = usb_alloc_urb(1, GFP_KERNEL); if (!u->urb) goto out_of_memory; - u->urb->transfer_buffer = ep->syncbuf + i * 4; + usb_fill_int_urb(u->urb, NULL, ep->pipe, ep->syncbuf + i * 4, 4, + snd_complete_urb, u, ep->syncinterval + 1); + u->urb->transfer_dma = ep->sync_dma + i * 4; - u->urb->transfer_buffer_length = 4; - u->urb->pipe = ep->pipe; u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP; u->urb->number_of_packets = 1; - u->urb->interval = 1 << ep->syncinterval; - u->urb->context = u; - u->urb->complete = snd_complete_urb; } ep->nurbs = SYNC_URBS;-- 2.17.1
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