Re:Re: [PATCH] USB: add usbfs ioctl to get specific superspeedplus rates

[Dingyan Li]

At 2023-07-25 22:08:44, "Oliver Neukum" <oneukum@xxxxxxxx> wrote:
>On 25.07.23 15:54, Dingyan Li wrote:
>
>> If we can't "deprecate" ioctls, can we change the returned contents of existing ones?
>
>No. Absolutely not. That is totally unacceptable. It would be much
>worse than just removing the support.
>
>	Regards
>		Oliver

Got it, I guess this is for backward-compatibility.

I also have another thought. USBDEVFS_CONNINFO_EX is kind of special and
used to retrieve contents of variable length. If you check proc_conninfo_ex(),
I think maybe we can append a new member to "struct usbdevfs_conninfo_ex"
without breaking backward-compatibility.

By this way, we can avoid adding a new ioctl. Or even more aggressively,
drop USBDEVFS_GET_SPEED and force everyone to use USBDEVFS_CONNINFO_EX
since it can also return device speed.


Regards,
Dingyan