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authorDavid Herrmann <dh.herrmann@googlemail.com>2012-06-10 15:16:25 +0200
committerJiri Kosina <jkosina@suse.cz>2012-06-18 13:42:03 +0200
commitfcfcf0deb89ece6eb9ae23768fec1bc1718f9b7f (patch)
treefcf86b0c55d4feea91ee00a6e59c423b6442708a /include/linux/uhid.h
parent3b3baa82e4306b5160692643fab2fa322ceb94f9 (diff)
HID: uhid: implement feature requests
HID standard allows sending a feature request to the device which is answered by an HID report. uhid implements this by sending a UHID_FEATURE event to user-space which then must answer with UHID_FEATURE_ANSWER. If it doesn't do this in a timely manner, the request is discarded silently. We serialize the feature requests, that is, there is always only a single active feature-request sent to user-space, other requests have to wait. HIDP and USB-HID do it the same way. Because we discard feature-requests silently, we must make sure to match a response to the corresponding request. We use sequence-IDs for this so user-space must copy the ID from the request into the answer. Feature-answers are ignored if they do not contain the same ID as the currently pending feature request. Internally, we must make sure that feature-requests are synchronized with UHID_DESTROY and close() events. We must not dead-lock when closing the HID device, either, so we have to use separate locks. Signed-off-by: David Herrmann <dh.herrmann@googlemail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'include/linux/uhid.h')
-rw-r--r--include/linux/uhid.h17
1 files changed, 17 insertions, 0 deletions
diff --git a/include/linux/uhid.h b/include/linux/uhid.h
index 2c972550a62..9c6974f1696 100644
--- a/include/linux/uhid.h
+++ b/include/linux/uhid.h
@@ -32,6 +32,8 @@ enum uhid_event_type {
UHID_OUTPUT,
UHID_OUTPUT_EV,
UHID_INPUT,
+ UHID_FEATURE,
+ UHID_FEATURE_ANSWER,
};
struct uhid_create_req {
@@ -73,6 +75,19 @@ struct uhid_output_ev_req {
__s32 value;
} __attribute__((__packed__));
+struct uhid_feature_req {
+ __u32 id;
+ __u8 rnum;
+ __u8 rtype;
+} __attribute__((__packed__));
+
+struct uhid_feature_answer_req {
+ __u32 id;
+ __u16 err;
+ __u16 size;
+ __u8 data[UHID_DATA_MAX];
+};
+
struct uhid_event {
__u32 type;
@@ -81,6 +96,8 @@ struct uhid_event {
struct uhid_input_req input;
struct uhid_output_req output;
struct uhid_output_ev_req output_ev;
+ struct uhid_feature_req feature;
+ struct uhid_feature_answer_req feature_answer;
} u;
} __attribute__((__packed__));