[PATCH] usb: Add 1ms delay after first Get Descriptor request

[Marek Vasut]

Logitech Unifying Receiver 046d:c52b bcdDevice 12.10 seems
sensitive about the first Get Descriptor request. If there
are any other requests in the same microframe, the device
reports bogus data, first of the descriptor parts is not
sent to the host. Wait over one microframe duration before
issuing subsequent requests to avoid probe failure with
this device, since it can be used to connect USB keyboards.

Signed-off-by: Marek Vasut <marex at denx.de>
---
Cc: Janne Grunau <j at jannau.net>
Cc: Mark Kettenis <kettenis at openbsd.org>
---
 common/usb.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/common/usb.c b/common/usb.c
index 6fcf1e8428e..ae9253dfc0e 100644
--- a/common/usb.c
+++ b/common/usb.c
@@ -999,6 +999,17 @@ static int usb_setup_descriptor(struct usb_device *dev, bool do_read)
 		err = get_descriptor_len(dev, 64, 8);
 		if (err)
 			return err;
+
+		/*
+		 * Logitech Unifying Receiver 046d:c52b bcdDevice 12.10 seems
+		 * sensitive about the first Get Descriptor request. If there
+		 * are any other requests in the same microframe, the device
+		 * reports bogus data, first of the descriptor parts is not
+		 * sent to the host. Wait over one microframe duration here
+		 * (1mS for USB 1.x , 125uS for USB 2.0) to avoid triggering
+		 * the issue.
+		 */
+		mdelay(1);
 	}
 
 	dev->epmaxpacketin[0] = dev->descriptor.bMaxPacketSize0;
-- 
2.35.1