Re: imx21-hcd bugs, device descriptor read/64, error -110

On Thu, 16 Aug 2007, Midhun Agnihotram wrote:

>   I am now developing a USB driver for IMX21 based on the OHCI S3C2410
> USB driver (since both are ARM based). I have made the changes in
> ohci.h for the register's physical addresses (I could not map every
> field - I did as many as I could map).
> 
>    My USB hub has been detected by the kernel. And there are three
> ports on the system - 1 USB host port and 2 USB device ports. The Hub
> says that 0 ports have been detected.
> 
> hub 1-0:1.0: USB hub found
> hub 1-0:1.0: 0 ports detected
> 
>     I could trace out that USB ports information is got from
> get_hub_descriptor method in hub.c. This sends a control message to
> get the descriptor. Here is where it is finding zero ports.
> 
>   What is this command? Isnt this command from the USB specification
> and hence should be a standard?

Yes.

> In that case I will not need to worry
> about the command.

Just the opposite: Because it is a standard, you _must_ support it!

>   What does this do? Is this returning 0 ports due to mismatched
> physical addresses? Where else could have this gone wrong?

Look at ohci_hub_descriptor() in ohci-hub.c.  The bNbrPorts field is 
filled in from ohci->num_ports.  If your driver doesn't set that field
correctly then nothing will work.

Alan Stern


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