From: anton <anton@openbsd.org>
Date: Sun, 29 Aug 2021 18:20:18 +0000 (+0000)
Subject: Some reports embeds multiple report IDs inside the same collection
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=4e984ffc3513a0515ac58821ae97194401123df4;p=openbsd

Some reports embeds multiple report IDs inside the same collection
causing ucc to only being able to attach to the last report ID. This in
turn is caused by hid_is_collection() only being able to observe an end
of collection item with the last report ID for the same collection.

Instead, change the matching of ucc to only consider report IDs with at
least one corresponding Consumer Control usage.

Fixes gnezdo@'s Google Pixel earbuds.
---

diff --git a/sys/dev/usb/ucc.c b/sys/dev/usb/ucc.c
index 4bf6b04fdb6..d7aba7b5f82 100644
--- a/sys/dev/usb/ucc.c
+++ b/sys/dev/usb/ucc.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ucc.c,v 1.15 2021/08/29 18:19:09 anton Exp $	*/
+/*	$OpenBSD: ucc.c,v 1.16 2021/08/29 18:20:18 anton Exp $	*/
 
 /*
  * Copyright (c) 2021 Anton Lindqvist <anton@openbsd.org>
@@ -98,6 +98,7 @@ int	ucc_enable(void *, int);
 void	ucc_set_leds(void *, int);
 int	ucc_ioctl(void *, u_long, caddr_t, int, struct proc *);
 
+int	ucc_hid_match(void *, int, uint8_t);
 int	ucc_hid_parse(struct ucc_softc *, void *, int);
 int	ucc_hid_parse_array(struct ucc_softc *, const struct hid_item *);
 int	ucc_hid_is_array(const struct hid_item *);
@@ -619,11 +620,10 @@ ucc_match(struct device *parent, void *match, void *aux)
 	int size;
 
 	uhidev_get_report_desc(uha->parent, &desc, &size);
-	if (!hid_is_collection(desc, size, uha->reportid,
-	    HID_USAGE2(HUP_CONSUMER, HUC_CONTROL)))
-		return UMATCH_NONE;
 	if (hid_report_size(desc, size, hid_input, uha->reportid) == 0)
 		return UMATCH_NONE;
+	if (!ucc_hid_match(desc, size, uha->reportid))
+		return UMATCH_NONE;
 
 	return UMATCH_IFACECLASS;
 }
@@ -830,6 +830,30 @@ ucc_ioctl(void *v, u_long cmd, caddr_t data, int flag, struct proc *p)
 	return -1;
 }
 
+/*
+ * Returns non-zero if the given report ID has at least one Consumer Control
+ * usage.
+ */
+int
+ucc_hid_match(void *desc, int descsiz, uint8_t repid)
+{
+	struct hid_item hi;
+	struct hid_data *hd;
+	int match = 0;
+
+	hd = hid_start_parse(desc, descsiz, hid_input);
+	while (hid_get_item(hd, &hi)) {
+		if (hi.report_ID == repid &&
+		    hi.kind == hid_input &&
+		    HID_GET_USAGE_PAGE(hi.usage) == HUP_CONSUMER) {
+			match = 1;
+			break;
+		}
+	}
+	hid_end_parse(hd);
+	return match;
+}
+
 /*
  * Parse the HID report and construct a mapping between the bits in the input
  * report and the corresponding pressed key.