From 23746a66d7d9e73402c68ef00d708796b97ebd72 Mon Sep 17 00:00:00 2001
From: Jiri Kosina <jkosina@suse.cz>
Date: Thu, 19 May 2011 17:58:07 +0200
Subject: HID: magicmouse: ignore 'ivalid report id' while switching
 modes

From: Jiri Kosina <jkosina@suse.cz>

commit 23746a66d7d9e73402c68ef00d708796b97ebd72 upstream.

The device reponds with 'invalid report id' when feature report switching it
into multitouch mode is sent to it.

This has been silently ignored before 0825411ade ("HID: bt: Wait for ACK
on Sent Reports"), but since this commit, it propagates -EIO from the _raw
callback .

So let the driver ignore -EIO as response to 0xd7,0x01 report, as that's
how the device reacts in normal mode.

Sad, but following reality.

This fixes https://bugzilla.kernel.org/show_bug.cgi?id=35022

Tested-by: Chase Douglas <chase.douglas@canonical.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 drivers/hid/hid-magicmouse.c |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

--- a/drivers/hid/hid-magicmouse.c
+++ b/drivers/hid/hid-magicmouse.c
@@ -501,9 +501,17 @@ static int magicmouse_probe(struct hid_d
 	}
 	report->size = 6;
 
+	/*
+	 * The device reponds with 'invalid report id' when feature
+	 * report switching it into multitouch mode is sent to it.
+	 *
+	 * This results in -EIO from the _raw low-level transport callback,
+	 * but there seems to be no other way of switching the mode.
+	 * Thus the super-ugly hacky success check below.
+	 */
 	ret = hdev->hid_output_raw_report(hdev, feature, sizeof(feature),
 			HID_FEATURE_REPORT);
-	if (ret != sizeof(feature)) {
+	if (ret != -EIO) {
 		hid_err(hdev, "unable to request touch data (%d)\n", ret);
 		goto err_stop_hw;
 	}