Re: [PATCH] ALSA: usb-audio: fix urb timeout with URB_ISO_ASAP flag

On 11/22/2022 4:46 PM, Takashi Iwai wrote:

On Tue, 22 Nov 2022 09:20:40 +0100, Michael Wu wrote:

...

When the loglevel is greater than 4, with a long messages printed on the console while playing or recording audios, the usb controller may become abnormal. `usb 1-2: timeout: still 1 active urbs on EP #1`

Fix it by configuring the transfer_flags URB_ISO_ASAP flag.

Signed-off-by: Michael Wu michael@allwinnertech.com

Hrm, that's somewhat backward action to the change we've done years ago, commit c75c5ab575af7db707689cdbb5a5c458e9a034bb:

 ALSA: USB: adjust for changed 3.8 USB API

 The recent changes in the USB API ("implement new semantics for
 URB_ISO_ASAP") made the former meaning of the URB_ISO_ASAP flag the
 default, and changed this flag to mean that URBs can be delayed.
 This is not the behaviour wanted by any of the audio drivers because
 it leads to discontinuous playback with very small period sizes.
 Therefore, our URBs need to be submitted without this flag.

I rather suspect that your problem is in the USB controller side.

thanks,

Takashi

Dear Takashi, thanks for the reminding. Let me check...