# Re: \[PATCH v2 1/6\] driver core: Move the "authorized" attribute from USB/Thunderbolt to core

- From: Dan Williams \<hidden\>
- Date: 2021-09-30 20:24:11 
- List: virtualization
- Page: https://ratatoskr.run/virtualization/2021/09/1527510
- Thread: https://ratatoskr.run/linux-pci/2021/09/1526447/t.md

```text
On Thu, Sep 30, 2021 at 12:50 PM Kuppuswamy, Sathyanarayanan
[ref] wrote:
>
>
>
> On 9/30/21 12:04 PM, Dan Williams wrote:
> >>> That's why it was highlighted in the changelog. Hopefully a
> >>> Thunderbolt developer can confirm if it is a non-issue.
> >>> Documentation/ABI/testing/sysfs-bus-thunderbolt does not seem to
> >>> answer this question about whether authorized_show and
> >>> authorized_store need to be symmetric.
> >> Apparently, Bolt does read it [1] and cares about it [2].
> > Ah, thank you!
> >
> > Yeah, looks like the conversion to bool was indeed too hopeful.
> >
>
> IIUC, the end result of value "2" in authorized sysfs is to just
> "authorize" or "de-authorize". In that case, can the user space
> driver adapt to this int->bool change? Just want to know the
> possibility.

ABIs are forever. The kernel has to uphold its contract to bolt that
it will return '2' and not '1' after '2' has been written.
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
```