diff options
Diffstat (limited to 'drivers/usb/gadget/function/u_audio.c')
| -rw-r--r-- | drivers/usb/gadget/function/u_audio.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/drivers/usb/gadget/function/u_audio.c b/drivers/usb/gadget/function/u_audio.c index 32ef22857083..ad16163b5ff8 100644 --- a/drivers/usb/gadget/function/u_audio.c +++ b/drivers/usb/gadget/function/u_audio.c @@ -96,11 +96,13 @@ static const struct snd_pcm_hardware uac_pcm_hardware = { }; static void u_audio_set_fback_frequency(enum usb_device_speed speed, + struct usb_ep *out_ep, unsigned long long freq, unsigned int pitch, void *buf) { u32 ff = 0; + const struct usb_endpoint_descriptor *ep_desc; /* * Because the pitch base is 1000000, the final divider here @@ -128,8 +130,13 @@ static void u_audio_set_fback_frequency(enum usb_device_speed speed, * byte fromat (that is Q16.16) * * ff = (freq << 16) / 8000 + * + * Win10 and OSX UAC2 drivers require number of samples per packet + * in order to honor the feedback value. + * Linux snd-usb-audio detects the applied bit-shift automatically. */ - freq <<= 4; + ep_desc = out_ep->desc; + freq <<= 4 + (ep_desc->bInterval - 1); } ff = DIV_ROUND_CLOSEST_ULL((freq * pitch), 1953125); @@ -267,7 +274,7 @@ static void u_audio_iso_fback_complete(struct usb_ep *ep, pr_debug("%s: iso_complete status(%d) %d/%d\n", __func__, status, req->actual, req->length); - u_audio_set_fback_frequency(audio_dev->gadget->speed, + u_audio_set_fback_frequency(audio_dev->gadget->speed, audio_dev->out_ep, params->c_srate, prm->pitch, req->buf); @@ -526,7 +533,7 @@ int u_audio_start_capture(struct g_audio *audio_dev) * be meauserd at start of playback */ prm->pitch = 1000000; - u_audio_set_fback_frequency(audio_dev->gadget->speed, + u_audio_set_fback_frequency(audio_dev->gadget->speed, ep, params->c_srate, prm->pitch, req_fback->buf); |