usb: gadget: uvc: Fix string descriptor STALL issue when multiple uvc functions are...

This patch solved the string descriptor STALL issue when we add multiple UVC
functions in a single configuration using a 'webcam.c' like composite driver.

Signed-off-by: Bhupesh Sharma <bhupesh.sharma@st.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

diff --git a/drivers/usb/gadget/f_uvc.c b/drivers/usb/gadget/f_uvc.c
index 2022fe492148b04a3fd8c1c4a6c9c1ab3a4ee942..054c35a22fbfcb81871adc7f34ca16bd4e2d5061 100644 (file)
--- a/drivers/usb/gadget/f_uvc.c
+++ b/drivers/usb/gadget/f_uvc.c
@@ -619,22 +619,28 @@ uvc_bind_config(struct usb_configuration *c,
        uvc->desc.fs_streaming = fs_streaming;
        uvc->desc.hs_streaming = hs_streaming;
 
-       /* Allocate string descriptor numbers. */
-       if ((ret = usb_string_id(c->cdev)) < 0)
-               goto error;
-       uvc_en_us_strings[UVC_STRING_ASSOCIATION_IDX].id = ret;
-       uvc_iad.iFunction = ret;
-
-       if ((ret = usb_string_id(c->cdev)) < 0)
-               goto error;
-       uvc_en_us_strings[UVC_STRING_CONTROL_IDX].id = ret;
-       uvc_control_intf.iInterface = ret;
-
-       if ((ret = usb_string_id(c->cdev)) < 0)
-               goto error;
-       uvc_en_us_strings[UVC_STRING_STREAMING_IDX].id = ret;
-       uvc_streaming_intf_alt0.iInterface = ret;
-       uvc_streaming_intf_alt1.iInterface = ret;
+       /* maybe allocate device-global string IDs, and patch descriptors */
+       if (uvc_en_us_strings[UVC_STRING_ASSOCIATION_IDX].id == 0) {
+               /* Allocate string descriptor numbers. */
+               ret = usb_string_id(c->cdev);
+               if (ret < 0)
+                       goto error;
+               uvc_en_us_strings[UVC_STRING_ASSOCIATION_IDX].id = ret;
+               uvc_iad.iFunction = ret;
+
+               ret = usb_string_id(c->cdev);
+               if (ret < 0)
+                       goto error;
+               uvc_en_us_strings[UVC_STRING_CONTROL_IDX].id = ret;
+               uvc_control_intf.iInterface = ret;
+
+               ret = usb_string_id(c->cdev);
+               if (ret < 0)
+                       goto error;
+               uvc_en_us_strings[UVC_STRING_STREAMING_IDX].id = ret;
+               uvc_streaming_intf_alt0.iInterface = ret;
+               uvc_streaming_intf_alt1.iInterface = ret;
+       }
 
        /* Register the function. */
        uvc->func.name = "uvc";