Hi Tak,
Dne 23. 08. 21 v 13:45 N. Chen napsal(a):
I'm attempting to create a composite gadget device that uses uac2 and
hid functions (speakerphone), using the latest kernel branch
(rpi-5.14.y) on a rpi4 device.
Windows10 host does not recognize the device as an audio usb device.
In order to get it recognized, I had to use c_sync in adaptive mode,
as well as make the following adjustments:
diff --git a/drivers/usb/gadget/function/f_uac2.c
b/drivers/usb/gadget/function/f_uac2.c
index ae29ff2b2b68..74a221939ca0 100644
--- a/drivers/usb/gadget/function/f_uac2.c
+++ b/drivers/usb/gadget/function/f_uac2.c
@@ -177,7 +177,7 @@ static struct uac2_input_terminal_descriptor
io_in_it_desc = {
.bDescriptorSubtype = UAC_INPUT_TERMINAL,
/* .bTerminalID = DYNAMIC */
- .wTerminalType = cpu_to_le16(UAC_INPUT_TERMINAL_UNDEFINED),
+ .wTerminalType = cpu_to_le16(UAC_INPUT_TERMINAL_MICROPHONE),
.bAssocTerminal = 0,
/* .bCSourceID = DYNAMIC */
.iChannelNames = 0,
@@ -205,7 +205,7 @@ static struct uac2_output_terminal_descriptor
io_out_ot_desc = {
.bDescriptorSubtype = UAC_OUTPUT_TERMINAL,
/* .bTerminalID = DYNAMIC */
- .wTerminalType = cpu_to_le16(UAC_OUTPUT_TERMINAL_UNDEFINED),
+ .wTerminalType = cpu_to_le16(UAC_OUTPUT_TERMINAL_SPEAKER),
.bAssocTerminal = 0,
/* .bSourceID = DYNAMIC */
/* .bCSourceID = DYNAMIC */
@@ -216,7 +216,7 @@ static struct uac2_ac_header_descriptor ac_hdr_desc = {
.bLength = sizeof ac_hdr_desc,
.bDescriptorType = USB_DT_CS_INTERFACE,
- .bDescriptorSubtype = UAC_MS_HEADER,
+ .bDescriptorSubtype = UAC_HEADER,
.bcdADC = cpu_to_le16(0x200),
.bCategory = UAC2_FUNCTION_IO_BOX,
/* .wTotalLength = DYNAMIC */
@@ -400,7 +400,7 @@ static struct usb_endpoint_descriptor fs_epin_desc = {
.bDescriptorType = USB_DT_ENDPOINT,
.bEndpointAddress = USB_DIR_IN,
- .bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_ASYNC,
+ .bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_SYNC,
/* .wMaxPacketSize = DYNAMIC */
.bInterval = 1,
};
@@ -409,7 +409,7 @@ static struct usb_endpoint_descriptor hs_epin_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
- .bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_ASYNC,
+ .bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_SYNC,
/* .wMaxPacketSize = DYNAMIC */
.bInterval = 4,
};
@@ -419,7 +419,7 @@ static struct usb_endpoint_descriptor ss_epin_desc = {
.bDescriptorType = USB_DT_ENDPOINT,
.bEndpointAddress = USB_DIR_IN,
- .bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_ASYNC,
+ .bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_SYNC,
/* .wMaxPacketSize = DYNAMIC */
.bInterval = 4,
};
--
There is a problem with max packet size calculation for EP-IN. It has
been discussed here recently
https://www.spinics.net/lists/linux-usb/msg214615.html
The simple change in the post above fixed Win10 enumeration for me and
another tester.
Also, there is a problem with feedback value calculation which Win10
ignores and keeps sending the same amount of samples. The fix is to send
number of samples per the actual packet, not per microframe for USB2. I
have not posted the attached patch as the whole patchset will most
likely be reverted for 5.15
https://www.spinics.net/lists/linux-usb/msg216042.html and I wanted to
wait till the situation works out to avoid confusion. In the attached
patch just change the ->c_srate_active to ->c_srate (the patch is on top
of more changes for switching between multiple samplerates).
Best regards,
Pavel.
>From 91dda032dd0958006a4e0a6f1f51526cefd95a1e Mon Sep 17 00:00:00 2001
From: Pavel Hofman <pavel.hofman@xxxxxxxxxxx>
Date: Thu, 12 Aug 2021 18:03:36 +0200
Subject: [PATCH 9/9] usb: gadget: u_audio: EP-OUT bInterval in fback frequency
Tests have revealed that Win10 and OSX UAC2 drivers require
the feedback frequency to be based on the actual packet
interval instead of on the USB2 microframe. Otherwise they
ignore the feedback value. Linux snd-usb-audio driver
detects the applied bitshift automatically.
The patch increases the bitshift in feedback frequency
calculation with EP-OUT bInterval value.
Signed-off-by: Pavel Hofman <pavel.hofman@xxxxxxxxxxx>
Tested-by: Henrik Enquist <henrik.enquist@xxxxxxxxx>
---
drivers/usb/gadget/function/u_audio.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/gadget/function/u_audio.c b/drivers/usb/gadget/function/u_audio.c
index a7896fbbab36..c70bdb565153 100644
--- a/drivers/usb/gadget/function/u_audio.c
+++ b/drivers/usb/gadget/function/u_audio.c
@@ -98,11 +98,13 @@ 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
@@ -130,8 +132,13 @@ 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 used bit shift automatically.
*/
- freq <<= 4;
+ ep_desc = out_ep->desc;
+ freq <<= 4 + (ep_desc->bInterval - 1);
}
ff = DIV_ROUND_CLOSEST_ULL((freq * pitch), 1953125);
@@ -263,7 +270,7 @@ 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_active, prm->pitch,
req->buf);
@@ -578,7 +585,7 @@ 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_active, prm->pitch,
req_fback->buf);
--
2.25.1
