On 05/03/2016 02:51 PM, Marek Vasut wrote:
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.
diff --git a/common/usb.c b/common/usb.c
+ /* + * 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);
Do we know the connection speed here? If so, we could sleep 1ms for USB1.x and 125us for USB2.x, thus reducing any performance impact. Still, this is a short delay that I think only happens once per actual device so perhaps it isn't worth it.
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