Re: arm: davinci: USB ethernet

From: ddegraff
Date: Tue Mar 20 2012 - 12:14:42 EST




On 03/20/2012 08:58 AM, Greg KH wrote:
On Mon, Mar 19, 2012 at 05:46:02AM -0500, Darryl wrote:
We are currently using a DA850 eval board but will eventually use a
custom board to interface host system to davinci using ethernet over
USB. We are using 2.6.37 with real-time patches, but a cursory look
(have not been able to build yet) at 3.3-rc7 suggests that the
issues noted below still exist.

There are currently two issues:

- Documentation/usb/hotplug.txt suggests that the drivers should be
built as modules so that such things as loading drivers and, in this
case, bringing up the interface, can ge moderated in user-space.
However, though the code can be build modular, the drivers are never
loaded. I suspect that one or more of the several relevant configs
(I see at least these: USB_MUSB_HDRC, USB_MUSB_DA8XX_GLUE,
USB_GADGET, USB_ETH, USB_GPIO_VBUS, NOP_USB_XCEIV, USB_ETH_RNDIS,
USB_OTG_UTILS) are required to be built in, but cannot seem to
determine the correct ones.
Do you have a userspace tool that will automatically load the proper
modules when they show up?
Busybox's mdev is currently intended for that. I've used udev for other projects, but we have a very limited space here.
More important at the moment, however, is getting notifications in userspace.

As for unwinding the .config issues, you will have to do this, based on
your own settings, not much we can do here.
It is my hope that the developers from TI and MonteVista will weigh in since I have, so far, unsuccessfully unwound the interactions.

- Even when compiling all the driver code built-in, neither the
plug-in nor plug-out event is propagated to user space, again, so
that the interface can be brought up.
How do you know it isn't showing up? What are you using to watch for
it? Are you using udev? Something else? devtmpfs?
As noted above, mdev, which is set as the userspace hotplug script (via echo its full path to /proc/sys/kernel/hotplug) which I have slightly modified to just log that it is being run, and see no output messages.

greg k-h
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