[3.11.y.z extended stable] Patch "HID: hid-elo: some systems cannot stomach work around" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    HID: hid-elo: some systems cannot stomach work around

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From b13200527af610231b3c331af39431d397a6a213 Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oneukum at suse.de>
Date: Wed, 25 Sep 2013 09:42:55 +0200
Subject: HID: hid-elo: some systems cannot stomach work around

commit 403cfb53fb450d53751fdc7ee0cd6652419612cf upstream.

Some systems although they have firmware class 'M', which usually
needs a work around to not crash, must not be subjected to the
work around because the work around crashes them. They cannot be
told apart by their own device descriptor, but as they are part
of compound devices, can be identified by looking at their siblings.

Signed-off-by: Oliver Neukum <oneukum at suse.de>
Signed-off-by: Jiri Kosina <jkosina at suse.cz>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/hid/hid-elo.c | 35 ++++++++++++++++++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/hid-elo.c b/drivers/hid/hid-elo.c
index f042a6c..4e49462 100644
--- a/drivers/hid/hid-elo.c
+++ b/drivers/hid/hid-elo.c
@@ -181,7 +181,40 @@ fail:
  */
 static bool elo_broken_firmware(struct usb_device *dev)
 {
-	return use_fw_quirk && le16_to_cpu(dev->descriptor.bcdDevice) == 0x10d;
+	struct usb_device *hub = dev->parent;
+	struct usb_device *child = NULL;
+	u16 fw_lvl = le16_to_cpu(dev->descriptor.bcdDevice);
+	u16 child_vid, child_pid;
+	int i;
+
+	if (!use_fw_quirk)
+		return false;
+	if (fw_lvl != 0x10d)
+		return false;
+
+	/* iterate sibling devices of the touch controller */
+	usb_hub_for_each_child(hub, i, child) {
+		child_vid = le16_to_cpu(child->descriptor.idVendor);
+		child_pid = le16_to_cpu(child->descriptor.idProduct);
+
+		/*
+		 * If one of the devices below is present attached as a sibling of
+		 * the touch controller then  this is a newer IBM 4820 monitor that
+		 * does not need the IBM-requested workaround if fw level is
+		 * 0x010d - aka 'M'.
+		 * No other HW can have this combination.
+		 */
+		if (child_vid==0x04b3) {
+			switch (child_pid) {
+			case 0x4676: /* 4820 21x Video */
+			case 0x4677: /* 4820 51x Video */
+			case 0x4678: /* 4820 2Lx Video */
+			case 0x4679: /* 4820 5Lx Video */
+				return false;
+			}
+		}
+	}
+	return true;
 }

 static int elo_probe(struct hid_device *hdev, const struct hid_device_id *id)
--
1.8.3.2