From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Date: Wed, 04 May 2016 12:25:12 +0200 Subject: [U-Boot] [PATCH 5/7] usb: Assure Get Descriptor request is in separate microframe In-Reply-To: <5729ACE1.50504@denx.de> References: <1462308680-9366-1-git-send-email-marex@denx.de> <1462308680-9366-5-git-send-email-marex@denx.de> <5729ACE1.50504@denx.de> Message-ID: <5729CE08.20501@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de 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 >> Cc: Chin Liang See >> Cc: Dinh Nguyen >> Cc: Hans de Goede >> Cc: Stefan Roese >> Cc: Stephen Warren >> --- >> 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