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[2/3] usb: raw-gadget: return USB_GADGET_DELAYED_STATUS from setup()

Message ID 739253b1efa3469e421c869c4520284e854dc48f.1693188390.git.andreyknvl@gmail.com
State New
Headers show
Series [1/3] usb: gadget: clarify usage of USB_GADGET_DELAYED_STATUS | expand

Commit Message

andrey.konovalov@linux.dev Aug. 28, 2023, 2:10 a.m. UTC 
From: Andrey Konovalov <andreyknvl@gmail.com>

Return USB_GADGET_DELAYED_STATUS from the setup() callback for 0-length
transfers as a workaround to stop some UDC drivers (e.g. dwc3) from
automatically proceeding with the status stage.

This workaround should be removed once all UDC drivers are fixed to
always delay the status stage until a response is queued to EP0.

Signed-off-by: Andrey Konovalov <andreyknvl@gmail.com>
---
 drivers/usb/gadget/legacy/raw_gadget.c | 11 +++++++++++
 1 file changed, 11 insertions(+)
diff mbox series

Patch

diff --git a/drivers/usb/gadget/legacy/raw_gadget.c b/drivers/usb/gadget/legacy/raw_gadget.c
index e549022642e5..b9ecc55a2ce2 100644
--- a/drivers/usb/gadget/legacy/raw_gadget.c
+++ b/drivers/usb/gadget/legacy/raw_gadget.c
@@ -25,6 +25,7 @@ 
 #include <linux/usb/ch9.h>
 #include <linux/usb/ch11.h>
 #include <linux/usb/gadget.h>
+#include <linux/usb/composite.h>
 
 #include <uapi/linux/usb/raw_gadget.h>
 
@@ -363,6 +364,16 @@  static int gadget_setup(struct usb_gadget *gadget,
 out_unlock:
 	spin_unlock_irqrestore(&dev->lock, flags);
 out:
+	if (ret == 0 && ctrl->wLength == 0) {
+		/*
+		 * Return USB_GADGET_DELAYED_STATUS as a workaround to stop
+		 * some UDC drivers (e.g. dwc3) from automatically proceeding
+		 * with the status stage for 0-length transfers.
+		 * Should be removed once all UDC drivers are fixed to always
+		 * delay the status stage until a response is queued to EP0.
+		 */
+		return USB_GADGET_DELAYED_STATUS;
+	}
 	return ret;
 }