[U-Boot] [PATCH] usb: Early failure when the first descriptor read fails, one way or another

[Marek Vasut <marex@denx.de>]

On Saturday, March 28, 2015 at 06:23:58 PM, Paul Kocialkowski wrote:
> When using an USB1 device on a controller that only supports USB2 (e.g.
> EHCI), reading the first descriptor will fail (read 0 byte), so we can
> abort the process at this point instead of failing later and wasting time.
> 
> Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
> ---
>  common/usb.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/common/usb.c b/common/usb.c
> index 32e15cd..d1b3316 100644
> --- a/common/usb.c
> +++ b/common/usb.c
> @@ -950,7 +950,7 @@ int usb_new_device(struct usb_device *dev)
>  	 */
>  #ifndef CONFIG_USB_XHCI
>  	err = usb_get_descriptor(dev, USB_DT_DEVICE, 0, desc, 64);
> -	if (err < 0) {
> +	if (err < sizeof(struct usb_device_descriptor)) {
>  		debug("usb_new_device: usb_get_descriptor() failed\n");
>  		return 1;
>  	}
> @@ -990,6 +990,9 @@ int usb_new_device(struct usb_device *dev)
>  	case 64:
>  		dev->maxpacketsize = PACKET_SIZE_64;
>  		break;
> +	default:
> +		debug("usb_new_device: invalid max packet size\n");

Hi,

since this is an error, this should probably be a printf(). Also,
to make the error message useful, it should state the invalid value
due to which it failed.

Thanks!

> +		return 1;
>  	}
>  	dev->devnum = addr;

Best regards,
Marek Vasut