diff options
| author | Benjamin Tissoires <bentiss@kernel.org> | 2025-08-21 16:38:14 +0200 |
|---|---|---|
| committer | Jiri Kosina <jkosina@suse.com> | 2025-09-12 17:11:55 +0200 |
| commit | 4c2c5ff9f3d72fb41f884f7c493ae9df83379340 (patch) | |
| tree | 6fcff8d14fcf39d53874735d08ab7f23aa3a593f | |
| parent | 4e411a3f7bba10579bbeec3af77ae2a05c9e4259 (diff) | |
HID: bpf: rescan the device for the group after a load/unload
When a BPF gets loaded, it was previously not possible to bind a
hid-generic device to hid-multitouch because the group was never
updated.
This change forces a rescan of the report descriptor after a bpf is
loaded/unloaded so we set up the proper group.
This was detected 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.
Suggested-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Signed-off-by: Jiri Kosina <jkosina@suse.com>
| -rw-r--r-- | drivers/hid/hid-core.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index cf68fdffe058..a5b3a8ca2fcb 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -944,6 +944,15 @@ static int hid_scan_report(struct hid_device *hid) hid->group = HID_GROUP_GENERIC; /* + * In case we are re-scanning after a BPF has been loaded, + * we need to use the bpf report descriptor, not the original one. + */ + if (hid->bpf_rdesc && hid->bpf_rsize) { + start = hid->bpf_rdesc; + end = start + hid->bpf_rsize; + } + + /* * The parsing is simpler than the one in hid_open_report() as we should * be robust against hid errors. Those errors will be raised by * hid_open_report() anyway. @@ -2728,6 +2737,12 @@ static int __hid_device_probe(struct hid_device *hdev, struct hid_driver *hdrv) int ret; if (!hdev->bpf_rsize) { + /* we keep a reference to the currently scanned report descriptor */ + const __u8 *original_rdesc = hdev->bpf_rdesc; + + if (!original_rdesc) + original_rdesc = hdev->dev_rdesc; + /* in case a bpf program gets detached, we need to free the old one */ hid_free_bpf_rdesc(hdev); @@ -2737,6 +2752,12 @@ static int __hid_device_probe(struct hid_device *hdev, struct hid_driver *hdrv) /* call_hid_bpf_rdesc_fixup will always return a valid pointer */ hdev->bpf_rdesc = call_hid_bpf_rdesc_fixup(hdev, hdev->dev_rdesc, &hdev->bpf_rsize); + + /* the report descriptor changed, we need to re-scan it */ + if (original_rdesc != hdev->bpf_rdesc) { + hdev->group = 0; + hid_set_group(hdev); + } } if (!hid_check_device_match(hdev, hdrv, &id)) |