[U-Boot] usb: Fail to get descriptor for USB 2.0 device

[Marek Vasut]

On 05/23/2018 07:00 PM, DATACOM - Paulo.Zaneti wrote:
> Hi,

Hi,

> When trying to migrate a board from u-boot version 2016.09 to version
> 2018.03, I found a problem with a USB 2.0 device which used to work on
> version 2016.09.

Does it still happen in u-boot/master ?

> In u-boot version 2016.09 the device appears like this:
> 
> 2: Mass Storage,  USB Revision 2.0
>  - SanDisk Cruzer Blade 200443243002FB509E64
>  - Class: (from Interface) Mass Storage
>  - PacketSize: 64  Configurations: 1
>  - Vendor: 0x0781  Product 0x5567 Version 1.38
>    Configuration: 1
>    - Interfaces: 1 Bus Powered 200mA
>      Interface: 0
>      - Alternate Setting 0, Endpoints: 2
>      - Class Mass Storage, Transp. SCSI, Bulk only
>      - Endpoint 1 In Bulk MaxPacket 512
>      - Endpoint 2 Out Bulk MaxPacket 512
> 
> 
> But in version 2018.03 I just can't start usb. It fails with following
> error:
> 
> => usb start
> starting USB...
> USB0:   USB EHCI 1.00
> scanning bus 0 for devices... EHCI timed out on TD - token=0x80008c80
> unable to get device descriptor (error=-1)
> 1 USB Device(s) found
> USB1:   USB EHCI 1.00
> scanning bus 1 for devices... 1 USB Device(s) found
>        scanning usb for storage devices... 0 Storage Device(s) found
> 
> 
> I did a "git bisect" and found that this problem is related to the
> following commit:
> 
> c008faa usb: Only get 64 bytes device descriptor for full speed devices
> 
> I am not an expert on USB, so I would like to ask for help on this issue.
> 
> In u-boot v2018.03, file common/usb.c, line 973, shouldn't the
> comparison be like this:
> 
>         if (do_read && dev->speed >= USB_SPEED_FULL) {
> 
> or, at list:
> 
>         if (do_read && (dev->speed == USB_SPEED_FULL || dev->speed ==
> USB_SPEED_HIGH)) {
> 
> 
> I would submit a patch for this, but I lack on USB knowledge for
> explaining the patch.
> 


-- 
Best regards,
Marek Vasut