This happened while Peter was trying to fix a Viewsonic device: the HID
device sending multiotuch data through a proprietary collection was
handled by hid-generic, and we don't have any way of attaching it to
hid-multitouch because the pre-scanning wasn't able to see the Contact
ID HID usage.

After a little of back and forth, it turns out that the best solution is
to re-scan the device when a report descriptor is changed from the BPF
point of view.

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
---
Benjamin Tissoires (2):
      HID: core: factor out hid_set_group()
      HID: bpf: rescan the device for the group after a load/unload

 drivers/hid/hid-core.c | 44 ++++++++++++++++++++++++++++++++++++--------
 1 file changed, 36 insertions(+), 8 deletions(-)
---
base-commit: f55f91622e6f10884d30049f6748588b3718eecd
change-id: 20250821-bpf-rescan-d4764865c67f

Best regards,
-- 
Benjamin Tissoires <bentiss@kernel.org>

On Thu, 21 Aug 2025, Benjamin Tissoires wrote:

> This happened while Peter was trying to fix a Viewsonic device: the HID
> device sending multiotuch data through a proprietary collection was
> handled by hid-generic, and we don't have any way of attaching it to
> hid-multitouch because the pre-scanning wasn't able to see the Contact
> ID HID usage.
> 
> After a little of back and forth, it turns out that the best solution is
> to re-scan the device when a report descriptor is changed from the BPF
> point of view.
> 
> Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
> ---
> Benjamin Tissoires (2):
>       HID: core: factor out hid_set_group()
>       HID: bpf: rescan the device for the group after a load/unload
> 
>  drivers/hid/hid-core.c | 44 ++++++++++++++++++++++++++++++++++++--------
>  1 file changed, 36 insertions(+), 8 deletions(-)

Now in hid.git#for-6.18/core. Thanks,

-- 
Jiri Kosina
SUSE Labs

On Thu, Aug 21, 2025 at 04:38:12PM +0200, Benjamin Tissoires wrote:
> This happened while Peter was trying to fix a Viewsonic device: the HID
> device sending multiotuch data through a proprietary collection was
> handled by hid-generic, and we don't have any way of attaching it to
> hid-multitouch because the pre-scanning wasn't able to see the Contact
> ID HID usage.
> 
> After a little of back and forth, it turns out that the best solution is
> to re-scan the device when a report descriptor is changed from the BPF
> point of view.
> 
> Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>

Thanks, this series looks good to me.

Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>

Cheers,
  Peter

> ---
> Benjamin Tissoires (2):
>       HID: core: factor out hid_set_group()
>       HID: bpf: rescan the device for the group after a load/unload
> 
>  drivers/hid/hid-core.c | 44 ++++++++++++++++++++++++++++++++++++--------
>  1 file changed, 36 insertions(+), 8 deletions(-)
> ---
> base-commit: f55f91622e6f10884d30049f6748588b3718eecd
> change-id: 20250821-bpf-rescan-d4764865c67f
> 
> Best regards,
> -- 
> Benjamin Tissoires <bentiss@kernel.org>
>