From: Marek Vasut <marex@denx.de>
Date: Wed, 27 Apr 2016 01:32:56 +0000 (+0200)
Subject: usb: Assure Get Descriptor request is in separate microframe
X-Git-Url: http://git.dujemihanovic.xyz/?a=commitdiff_plain;h=ef71290be9b70d8cfa63b506c7d93c5069f63c42;p=u-boot.git

usb: Assure Get Descriptor request is in separate microframe

The Kingston DT Ultimate USB 3.0 stick is sensitive to this first
Get Descriptor request and if the request is not in a separate
microframe, the stick refuses to operate. Add slight delay, which
is enough for one microframe to pass on any USB spec revision.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Chin Liang See <clsee@altera.com>
Cc: Dinh Nguyen <dinguyen@opensource.altera.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Stefan Roese <sr@denx.de>
Cc: Stephen Warren <swarren@nvidia.com>
---

diff --git a/common/usb.c b/common/usb.c
index 205041b6a6..8d9efe516b 100644
--- a/common/usb.c
+++ b/common/usb.c
@@ -1077,6 +1077,14 @@ int usb_select_config(struct usb_device *dev)
 	le16_to_cpus(&dev->descriptor.idProduct);
 	le16_to_cpus(&dev->descriptor.bcdDevice);
 
+	/*
+	 * Kingston DT Ultimate 32GB USB 3.0 seems to be extremely sensitive
+	 * about this first Get Descriptor request. If there are any other
+	 * requests in the first microframe, the stick crashes. Wait about
+	 * one microframe duration here (1mS for USB 1.x , 125uS for USB 2.0).
+	 */
+	mdelay(1);
+
 	/* only support for one config for now */
 	err = usb_get_configuration_len(dev, 0);
 	if (err >= 0) {