linux-kernel - [PATCH 2/3] HID: surface-hid: Use correct event registry for managing HID events

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Message-Id: <20211021130904.862610-3-luzmaximilian@gmail.com>
Date:   Thu, 21 Oct 2021 15:09:03 +0200
From:   Maximilian Luz <luzmaximilian@...il.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Maximilian Luz <luzmaximilian@...il.com>,
        Hans de Goede <hdegoede@...hat.com>,
        Mark Gross <markgross@...nel.org>,
        Jiri Kosina <jikos@...nel.org>,
        Benjamin Tissoires <benjamin.tissoires@...hat.com>,
        platform-driver-x86@...r.kernel.org, linux-input@...r.kernel.org,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: [PATCH 2/3] HID: surface-hid: Use correct event registry for managing HID events

Until now, we have only ever seen the REG-category registry being used
on devices addressed with target ID 2. In fact, we have only ever seen
Surface Aggregator Module (SAM) HID devices with target ID 2. For those
devices, the registry also has to be addressed with target ID 2.

Some devices, like the new Surface Laptop Studio, however, address their
HID devices on target ID 1. As a result of this, any target ID 2
commands time out. This includes event management commands addressed to
the target ID 2 REG-category registry. For these devices, the registry
has to be addressed via target ID 1 instead.

We therefore assume that the target ID of the registry to be used
depends on the target ID of the respective device. Implement this
accordingly.

Note that we currently allow the surface HID driver to only load against
devices with target ID 2, so these timeouts are not happening (yet).
This is just a preparation step before we allow the driver to load
against all target IDs.

Cc: stable@...r.kernel.org # 5.14+
Signed-off-by: Maximilian Luz <luzmaximilian@...il.com>
---
 drivers/hid/surface-hid/surface_hid.c         | 2 +-
 include/linux/surface_aggregator/controller.h | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/hid/surface-hid/surface_hid.c b/drivers/hid/surface-hid/surface_hid.c
index a3a70e4f3f6c..daa452367c0b 100644
--- a/drivers/hid/surface-hid/surface_hid.c
+++ b/drivers/hid/surface-hid/surface_hid.c
@@ -209,7 +209,7 @@ static int surface_hid_probe(struct ssam_device *sdev)

 	shid->notif.base.priority = 1;
 	shid->notif.base.fn = ssam_hid_event_fn;
-	shid->notif.event.reg = SSAM_EVENT_REGISTRY_REG;
+	shid->notif.event.reg = SSAM_EVENT_REGISTRY_REG(sdev->uid.target);
 	shid->notif.event.id.target_category = sdev->uid.category;
 	shid->notif.event.id.instance = sdev->uid.instance;
 	shid->notif.event.mask = SSAM_EVENT_MASK_STRICT;
diff --git a/include/linux/surface_aggregator/controller.h b/include/linux/surface_aggregator/controller.h
index 068e1982ad37..74bfdffaf7b0 100644
--- a/include/linux/surface_aggregator/controller.h
+++ b/include/linux/surface_aggregator/controller.h
@@ -792,8 +792,8 @@ enum ssam_event_mask {
 #define SSAM_EVENT_REGISTRY_KIP	\
 	SSAM_EVENT_REGISTRY(SSAM_SSH_TC_KIP, 0x02, 0x27, 0x28)

-#define SSAM_EVENT_REGISTRY_REG \
-	SSAM_EVENT_REGISTRY(SSAM_SSH_TC_REG, 0x02, 0x01, 0x02)
+#define SSAM_EVENT_REGISTRY_REG(tid)\
+	SSAM_EVENT_REGISTRY(SSAM_SSH_TC_REG, tid, 0x01, 0x02)

 /**
  * enum ssam_event_notifier_flags - Flags for event notifiers.
-- 
2.33.1