Re: [RFC/PATCH 2/2] usb: ehci: Add support for SINGLE_STEP_SET_FEATURE test of EHSET

[Felipe Balbi <balbi@ti.com>]

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On Thu, Jul 25, 2013 at 03:44:20PM -0400, Alan Stern wrote:
> On Thu, 25 Jul 2013, Greg KH wrote:
> 
> > On Tue, Jul 02, 2013 at 08:13:52PM -0700, Jack Pham wrote:
> > > From: Manu Gautam <mgautam@codeaurora.org>
> > > 
> > > The USB Embedded High-speed Host Electrical Test (EHSET) defines the
> > > SINGLE_STEP_SET_FEATURE test as follows:
> > > 
> > > 1) The host enumerates the test device with VID:0x1A0A, PID:0x0108
> > > 2) The host sends the SETUP stage of a GetDescriptor(Device)
> > > 3) The device ACKs the request
> > > 4) The host issues SOFs for 15 seconds allowing the test operator to
> > >    raise the scope trigger just above the SOF voltage level
> > > 5) The host sends the IN packet
> > > 6) The device sends data in response, triggering the scope
> > > 7) The host sends an ACK in response to the data
> > > 
> > > This patch adds additional handling to the EHCI hub driver and allows
> > > the EHSET driver to initiate this test mode by issuing a a SetFeature
> > > request to the root hub with a Test Selector value of 0x06. From there
> > > it mimics ehci_urb_enqueue() but separately submits QTDs for the
> > > SETUP and DATA/STATUS stages in order to insert a delay in between.
> > > 
> > > Signed-off-by: Manu Gautam <mgautam@codeaurora.org>
> > > Signed-off-by: Jack Pham <jackp@codeaurora.org>
> > 
> > Alan, any thoughts about this patch?
> 
> Sorry, this slipped my mind.
> 
> It looks okay.  I haven't tested it yet (and it's so specialized that
> it probably will never receive very much testing).  It is somewhat 
> fragile, in that it copies part of usbcore into ehci-hcd; updates to 
> the core will have to be mirrored in the driver.
> 
> On the other hand, there's no real reason to reject it, and it could 
> end up helping people who want to test new USB devices.  So...
> 
> Acked-by: Alan Stern <stern@rowland.harvard.edu>

Wait a minute, didn't we discuss a while back that these test features
should be built into usbcore so that we could have a usbcv clone for
linux ?

-- 
balbi

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