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Message-ID: <lsq.1461711744.652671586@decadent.org.uk>
Date: Wed, 27 Apr 2016 01:02:24 +0200
From: Ben Hutchings <ben@...adent.org.uk>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC: akpm@...ux-foundation.org,
"Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
"Oliver Neukum" <oneukum@...e.com>
Subject: [PATCH 3.2 005/115] usb: retry reset if a device times out
3.2.80-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Oliver Neukum <oneukum@...e.com>
commit 264904ccc33c604d4b3141bbd33808152dfac45b upstream.
Some devices I got show an inability to operate right after
power on if they are already connected. They are beyond recovery
if the descriptors are requested multiple times. So in case of
a timeout we rather bail early and reset again. But it must be
done only on the first loop lest we get into a reset/time out
spiral that can be overcome with a retry.
This patch is a rework of a patch that fell through the cracks.
http://www.spinics.net/lists/linux-usb/msg103263.html
Signed-off-by: Oliver Neukum <oneukum@...e.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
drivers/usb/core/hub.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -3171,7 +3171,13 @@ hub_port_init (struct usb_hub *hub, stru
r = -EPROTO;
break;
}
- if (r == 0)
+ /*
+ * Some devices time out if they are powered on
+ * when already connected. They need a second
+ * reset. But only on the first attempt,
+ * lest we get into a time out/reset loop
+ */
+ if (r == 0 || (r == -ETIMEDOUT && j == 0))
break;
}
udev->descriptor.bMaxPacketSize0 =
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