Re: [Alsa-user] usbaudio - Stream start causes multiple urbs to be sent rapidly to isosynchronous and sync endpoints

2015-09-14 Thread Clemens Ladisch
Phil Quinton wrote: > "They are submitted to the endpoint's queue. The actual transmission > is managed by the controller's hardware and happens later, once per > microframe." > > Okay, but why are the 12 urbs (4 for sync) despatched one every > microframe ONLY on the initial start of a stream? I

Re: [Alsa-user] usbaudio - Stream start causes multiple urbs to be sent rapidly to isosynchronous and sync endpoints

2015-09-14 Thread Phil Quinton
"They are submitted to the endpoint's queue. The actual transmission is managed by the controller's hardware and happens later, once per microframe." Okay, but why are the 12 urbs (4 for sync) despatched one every microframe ONLY on the initial start of a stream? After they have been sent it bac

Re: [Alsa-user] usbaudio - Stream start causes multiple urbs to be sent rapidly to isosynchronous and sync endpoints

2015-09-13 Thread Clemens Ladisch
Phil Quinton wrote: > When an audio stream starts (play), 12 urbs get sent (very close > together) to the main isosynchronous end point They are submitted to the endpoint's queue. The actual transmission is managed by the controller's hardware and happens later, once per microframe. > This is ca

[Alsa-user] usbaudio - Stream start causes multiple urbs to be sent rapidly to isosynchronous and sync endpoints

2015-09-12 Thread Phil Quinton
Hi, I'm currently building a DIY High speed usb audio device and have come across some stange behaviour. When an audio stream starts (play), 12 urbs get sent (very close together) to the main isosynchronous end point, 4 urbs get sent to the sync endpoint. This is causing a buffer overrun on my DIY