[PATCH 5.15 33/35] usb: gadget: f_uac2: fix superspeed transfer

Greg Kroah-Hartman
2022-09-16T10:20:48Z

From: Jing Leng <jleng@ambarella.com>

commit f511aef2ebe5377d4c263842f2e0c0b8e274e8e5 upstream.

On page 362 of the USB3.2 specification (
https://usb.org/sites/default/files/usb_32_20210125.zip),
The 'SuperSpeed Endpoint Companion Descriptor' shall only be returned
by Enhanced SuperSpeed devices that are operating at Gen X speed.
Each endpoint described in an interface is followed by a 'SuperSpeed
Endpoint Companion Descriptor'.

If users use SuperSpeed UDC, host can't recognize the device if endpoint
doesn't have 'SuperSpeed Endpoint Companion Descriptor' followed.

Currently in the uac2 driver code:
1. ss_epout_desc_comp follows ss_epout_desc;
2. ss_epin_fback_desc_comp follows ss_epin_fback_desc;
3. ss_epin_desc_comp follows ss_epin_desc;
4. Only ss_ep_int_desc endpoint doesn't have 'SuperSpeed Endpoint
Companion Descriptor' followed, so we should add it.

Fixes: eaf6cbe09920 ("usb: gadget: f_uac2: add volume and mute support")
Cc: stable <stable@kernel.org>
Signed-off-by: Jing Leng <jleng@ambarella.com>
Signed-off-by: Jack Pham <quic_jackp@quicinc.com>
Link: https://lore.kernel.org/r/20220721014815.14453-1-quic_jackp@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/gadget/function/f_uac2.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)

--- a/drivers/usb/gadget/function/f_uac2.c
+++ b/drivers/usb/gadget/function/f_uac2.c
@@ -281,6 +281,12 @@ static struct usb_endpoint_descriptor ss
.bInterval = 4,
};

+static struct usb_ss_ep_comp_descriptor ss_ep_int_desc_comp = {
+ .bLength = sizeof(ss_ep_int_desc_comp),
+ .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
+ .wBytesPerInterval = cpu_to_le16(6),
+};
+
/* Audio Streaming OUT Interface - Alt0 */
static struct usb_interface_descriptor std_as_out_if0_desc = {
.bLength = sizeof std_as_out_if0_desc,
@@ -594,7 +600,8 @@ static struct usb_descriptor_header *ss_
(struct usb_descriptor_header *)&in_feature_unit_desc,
(struct usb_descriptor_header *)&io_out_ot_desc,

- (struct usb_descriptor_header *)&ss_ep_int_desc,
+ (struct usb_descriptor_header *)&ss_ep_int_desc,
+ (struct usb_descriptor_header *)&ss_ep_int_desc_comp,

(struct usb_descriptor_header *)&std_as_out_if0_desc,
(struct usb_descriptor_header *)&std_as_out_if1_desc,
@@ -721,6 +728,7 @@ static void setup_headers(struct f_uac2_
struct usb_ss_ep_comp_descriptor *epout_desc_comp = NULL;
struct usb_ss_ep_comp_descriptor *epin_desc_comp = NULL;
struct usb_ss_ep_comp_descriptor *epin_fback_desc_comp = NULL;
+ struct usb_ss_ep_comp_descriptor *ep_int_desc_comp = NULL;
struct usb_endpoint_descriptor *epout_desc;
struct usb_endpoint_descriptor *epin_desc;
struct usb_endpoint_descriptor *epin_fback_desc;
@@ -748,6 +756,7 @@ static void setup_headers(struct f_uac2_
epin_fback_desc = &ss_epin_fback_desc;
epin_fback_desc_comp = &ss_epin_fback_desc_comp;
ep_int_desc = &ss_ep_int_desc;
+ ep_int_desc_comp = &ss_ep_int_desc_comp;
}

i = 0;
@@ -776,8 +785,11 @@ static void setup_headers(struct f_uac2_
if (EPOUT_EN(opts))
headers[i++] = USBDHDR(&io_out_ot_desc);

- if (FUOUT_EN(opts) || FUIN_EN(opts))
+ if (FUOUT_EN(opts) || FUIN_EN(opts)) {
headers[i++] = USBDHDR(ep_int_desc);
+ if (ep_int_desc_comp)
+ headers[i++] = USBDHDR(ep_int_desc_comp);
+ }

if (EPOUT_EN(opts)) {
headers[i++] = USBDHDR(&std_as_out_if0_desc);