On Tue, Apr 25, 2023 at 02:58:53PM +0200, Konrad Gräfe wrote:
>
> As the CDC-ECM specification states the host MAC address must be sent to
> the host as an uppercase hexadecimal string:
> The Unicode character is chosen from the set of values 30h through
> 39h and 41h through 46h (0-9 and A-F).
>
> However, snprintf(.., "%pm", ..) generates a lowercase MAC address
> string. While most host drivers are tolerant to this, UsbNcm.sys on
> Windows 10 is not. Instead it uses a different MAC address with all
> bytes set to zero including and after the first byte containing a
> lowercase letter. On Windows 11 Microsoft fixed it, but apparently they
> did not backport the fix.
>
> This change fixes the issue by upper-casing the MAC to comply with the
> specification.
>
> Signed-off-by: Konrad Gräfe <k.graefe@xxxxxxxxxxx>
> ---
> drivers/usb/gadget/function/u_ether.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
>
> diff --git drivers/usb/gadget/function/u_ether.c drivers/usb/gadget/function/u_ether.c
> index 6956ad8ba8dd..49d29b04ef93 100644
> --- drivers/usb/gadget/function/u_ether.c
> +++ drivers/usb/gadget/function/u_ether.c
> @@ -958,6 +958,7 @@ EXPORT_SYMBOL_GPL(gether_get_host_addr);
> int gether_get_host_addr_cdc(struct net_device *net, char *host_addr, int len)
> {
> struct eth_dev *dev;
> + int i, slen;
>
> if (len < 13)
> return -EINVAL;
> @@ -965,7 +966,14 @@ int gether_get_host_addr_cdc(struct net_device *net, char *host_addr, int len)
> dev = netdev_priv(net);
> snprintf(host_addr, len, "%pm", dev->host_mac);
>
> - return strlen(host_addr);
> +
> + slen = strlen(host_addr);
> +
> + for(i = 0; i < slen; i++) {
> + host_addr[i] = toupper(host_addr[i]);
> + }
> +
> + return slen;
> }
> EXPORT_SYMBOL_GPL(gether_get_host_addr_cdc);
>
>
Hi,
This is the friendly patch-bot of Greg Kroah-Hartman. You have sent him
a patch that has triggered this response. He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created. Hopefully you will not take offence and will fix the problem
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kernel tree.
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