# Re: \[RFCv2 0/8\] USI stylus support series

- From: Hyungwoo Yang \<hidden\>
- Date: 2021-11-30 06:36:35 
- List: linux-input
- Page: https://ratatoskr.run/linux-input/2021/11/1590886
- Thread: https://ratatoskr.run/linux-input/2021/11/1587749/t.md

```text
Hi Tero,


I have a question. As you know, USI provides a room for vendors to differentiate their stylus. If a vendor wants to add reach features to differentiate their stylus. Do you think the vendor needs to come up with like HID-USI-<vendor>.c to configure the corresponding usages(vendor-defined data) ? or we should use other approach ? like register callbacks via HID-core ?

-Hyungwoo

On 11/26/21 5:01 AM, Tero Kristo wrote:
> Hi,
>
> This series is an update based on comments from Benjamin. What is done
> is this series is to ditch the separate hid-driver for USI, and add the
> generic support to core layers. This part basically brings the support
> for providing USI events, without programmability (patches 1-6).
>
> Additionally, a HID-BPF based sample is provided which can be used to
> program / query pen parameters in comparison to the old driver level
> implementation (patches 7-8, patch #8 is an incremental change on top of
> patch #7 which just converts the fifo to socket so that the client can
> also get results back from the server.)
>
> The whole series is based on top of Benjamin's hid-bpf support work, and
> I've pushed a branch at [1] with a series that works and brings in
> the dependency. There are also a few separate patches in this series to
> fix the problems I found from Benjamin's initial work for hid-bpf; I
> wasn't able to get things working without those. The branch is also
> based on top of 5.16-rc2 which required some extra changes to the
> patches from Benjamin.
>
> -Tero
>
> [1] https://github.com/t-kristo/linux/tree/usi-5.16-rfc-v2-bpf
>
>
>
>
```