* [PATCH] ALSA: usb: use multiple packets per urb for Wireless USB inbound audio
@ 2013-11-26 19:58 Thomas Pugliese
2013-11-27 10:56 ` Takashi Iwai
0 siblings, 1 reply; 2+ messages in thread
From: Thomas Pugliese @ 2013-11-26 19:58 UTC (permalink / raw)
To: alsa-devel; +Cc: tiwai, Thomas Pugliese
For Wireless USB audio devices, use multiple isoc packets per URB for
inbound endpoints with a datainterval < 5. This allows the WUSB host
controller to take advantage of bursting to service endpoints whose
logical polling interval is less than the 4ms minimum polling interval
limit in WUSB.
Signed-off-by: Thomas Pugliese <thomas.pugliese@gmail.com>
---
sound/usb/endpoint.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index b9ba0fc..83aabea2 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -636,8 +636,22 @@ static int data_ep_set_params(struct snd_usb_endpoint *ep,
if (usb_pipein(ep->pipe) ||
snd_usb_endpoint_implicit_feedback_sink(ep)) {
+ urb_packs = packs_per_ms;
+ /*
+ * Wireless devices can poll at a max rate of once per 4ms.
+ * For dataintervals less than 5, increase the packet count to
+ * allow the host controller to use bursting to fill in the
+ * gaps.
+ */
+ if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_WIRELESS) {
+ int interval = ep->datainterval;
+ while (interval < 5) {
+ urb_packs <<= 1;
+ ++interval;
+ }
+ }
/* make capture URBs <= 1 ms and smaller than a period */
- urb_packs = min(max_packs_per_urb, packs_per_ms);
+ urb_packs = min(max_packs_per_urb, urb_packs);
while (urb_packs > 1 && urb_packs * maxsize >= period_bytes)
urb_packs >>= 1;
ep->nurbs = MAX_URBS;
--
1.7.10.4
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] ALSA: usb: use multiple packets per urb for Wireless USB inbound audio
2013-11-26 19:58 [PATCH] ALSA: usb: use multiple packets per urb for Wireless USB inbound audio Thomas Pugliese
@ 2013-11-27 10:56 ` Takashi Iwai
0 siblings, 0 replies; 2+ messages in thread
From: Takashi Iwai @ 2013-11-27 10:56 UTC (permalink / raw)
To: Thomas Pugliese; +Cc: alsa-devel
At Tue, 26 Nov 2013 13:58:15 -0600,
Thomas Pugliese wrote:
>
> For Wireless USB audio devices, use multiple isoc packets per URB for
> inbound endpoints with a datainterval < 5. This allows the WUSB host
> controller to take advantage of bursting to service endpoints whose
> logical polling interval is less than the 4ms minimum polling interval
> limit in WUSB.
>
> Signed-off-by: Thomas Pugliese <thomas.pugliese@gmail.com>
Thanks, applied now.
Takashi
> ---
> sound/usb/endpoint.c | 16 +++++++++++++++-
> 1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
> index b9ba0fc..83aabea2 100644
> --- a/sound/usb/endpoint.c
> +++ b/sound/usb/endpoint.c
> @@ -636,8 +636,22 @@ static int data_ep_set_params(struct snd_usb_endpoint *ep,
> if (usb_pipein(ep->pipe) ||
> snd_usb_endpoint_implicit_feedback_sink(ep)) {
>
> + urb_packs = packs_per_ms;
> + /*
> + * Wireless devices can poll at a max rate of once per 4ms.
> + * For dataintervals less than 5, increase the packet count to
> + * allow the host controller to use bursting to fill in the
> + * gaps.
> + */
> + if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_WIRELESS) {
> + int interval = ep->datainterval;
> + while (interval < 5) {
> + urb_packs <<= 1;
> + ++interval;
> + }
> + }
> /* make capture URBs <= 1 ms and smaller than a period */
> - urb_packs = min(max_packs_per_urb, packs_per_ms);
> + urb_packs = min(max_packs_per_urb, urb_packs);
> while (urb_packs > 1 && urb_packs * maxsize >= period_bytes)
> urb_packs >>= 1;
> ep->nurbs = MAX_URBS;
> --
> 1.7.10.4
>
> _______________________________________________
> Alsa-devel mailing list
> Alsa-devel@alsa-project.org
> http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
>
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2013-11-27 10:56 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2013-11-26 19:58 [PATCH] ALSA: usb: use multiple packets per urb for Wireless USB inbound audio Thomas Pugliese
2013-11-27 10:56 ` Takashi Iwai
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.