On 05/04/2016 10:03 AM, Stefan Roese wrote: > On 03.05.2016 22:51, 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. >> >> Signed-off-by: Marek Vasut <ma...@denx.de> >> Cc: Chin Liang See <cl...@altera.com> >> Cc: Dinh Nguyen <dingu...@opensource.altera.com> >> Cc: Hans de Goede <hdego...@redhat.com> >> Cc: Stefan Roese <s...@denx.de> >> Cc: Stephen Warren <swar...@nvidia.com> >> --- >> common/usb.c | 8 ++++++++ >> 1 file changed, 8 insertions(+) >> >> diff --git a/common/usb.c b/common/usb.c >> index 205041b..8d9efe5 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) { >> > > Again my question, if this problem also occurs on other platforms > with this USB key. A 1ms delay is not really a big deal, but its > my general feeling that we should manifest such changes by testing > on different platforms.
I tested it by connecting the bus analyzer between the stick and socfpga and between the stick and x86 host. I wouldn't be able to come up with this solution. btw. any ehci ends up inserting these control requests into separate microframes, but we need the mdelay to also cater for ohci/uhci, which has longer frames (1ms). -- Best regards, Marek Vasut _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot