HID: hid-sony.c: Fix sending Output reports to the Sixaxis

The Sixaxis does not want the report_id as part of the data packet in
Output reports, so we have to discard buf[0] when sending the actual
control message.

Add also some documentation about that and about why
hdev->hid_output_raw_report needs to be overridden.

Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 20 insertions, 0 deletions

diff --git a/drivers/hid/hid-sony.c b/drivers/hid/hid-sony.c
index 68d7b36e31e4..93819a08121a 100644
--- a/drivers/hid/hid-sony.c
+++ b/drivers/hid/hid-sony.c
@@ -46,6 +46,16 @@ static __u8 *sony_report_fixup(struct hid_device *hdev, __u8 *rdesc,
         return rdesc;
 }
 
+/*
+ * The Sony Sixaxis does not handle HID Output Reports on the Interrupt EP
+ * like it should according to usbhid/hid-core.c::usbhid_output_raw_report()
+ * so we need to override that forcing HID Output Reports on the Control EP.
+ *
+ * There is also another issue about HID Output Reports via USB, the Sixaxis
+ * does not want the report_id as part of the data packet, so we have to
+ * discard buf[0] when sending the actual control message, even for numbered
+ * reports, humpf!
+ */
 static int sixaxis_usb_output_raw_report(struct hid_device *hid, __u8 *buf,
                 size_t count, unsigned char report_type)
 {
@@ -55,6 +65,12 @@ static int sixaxis_usb_output_raw_report(struct hid_device *hid, __u8 *buf,
         int report_id = buf[0];
         int ret;
 
+        if (report_type == HID_OUTPUT_REPORT) {
+                /* Don't send the Report ID */
+                buf++;
+                count--;
+        }
+
         ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
                 HID_REQ_SET_REPORT,
                 USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
@@ -62,6 +78,10 @@ static int sixaxis_usb_output_raw_report(struct hid_device *hid, __u8 *buf,
                 interface->desc.bInterfaceNumber, buf, count,
                 USB_CTRL_SET_TIMEOUT);
 
+        /* Count also the Report ID, in case of an Output report. */
+        if (ret > 0 && report_type == HID_OUTPUT_REPORT)
+                ret++;
+
         return ret;
 }