HID: multitouch: do not retrieve all reports for all devices

[ Upstream commit b897f6db3ae2cd9a42377f8b1865450f34ceff0e ]

We already have in place a quirk for Windows 8 devices, but it looks
like the Surface Cover are not conforming to it.
Given that we are only interested in 3 feature reports (the ones that
the Windows driver retrieves), we should be safe to unconditionally apply
the quirk to everybody.

In case there is an issue with a controller, we can always mark it as such
in the transport driver, and hid-multitouch won't try to retrieve the
feature report.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 40 insertions, 36 deletions

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 84c56e645fe8..89e9032ab1e7 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -108,6 +108,7 @@ struct mt_device {
         int cc_value_index;     /* contact count value index in the field */
         unsigned last_slot_field;       /* the last field of a slot */
         unsigned mt_report_id;  /* the report ID of the multitouch device */
+        unsigned long initial_quirks;   /* initial quirks state */
         __s16 inputmode;        /* InputMode HID feature, -1 if non-existent */
         __s16 inputmode_index;  /* InputMode HID feature index in the report */
         __s16 maxcontact_report_id;     /* Maximum Contact Number HID feature,
@@ -318,13 +319,10 @@ static void mt_get_feature(struct hid_device *hdev, struct hid_report *report)
         u8 *buf;
 
         /*
-         * Only fetch the feature report if initial reports are not already
-         * been retrieved. Currently this is only done for Windows 8 touch
-         * devices.
+         * Do not fetch the feature report if the device has been explicitly
+         * marked as non-capable.
          */
-        if (!(hdev->quirks & HID_QUIRK_NO_INIT_REPORTS))
-                return;
-        if (td->mtclass.name != MT_CLS_WIN_8)
+        if (td->initial_quirks & HID_QUIRK_NO_INIT_REPORTS)
                 return;
 
         buf = hid_alloc_report_buf(report, GFP_KERNEL);
@@ -1085,36 +1083,6 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
                 }
         }
 
-        /* This allows the driver to correctly support devices
-         * that emit events over several HID messages.
-         */
-        hdev->quirks |= HID_QUIRK_NO_INPUT_SYNC;
-
-        /*
-         * This allows the driver to handle different input sensors
-         * that emits events through different reports on the same HID
-         * device.
-         */
-        hdev->quirks |= HID_QUIRK_MULTI_INPUT;
-        hdev->quirks |= HID_QUIRK_NO_EMPTY_INPUT;
-
-        /*
-         * Handle special quirks for Windows 8 certified devices.
-         */
-        if (id->group == HID_GROUP_MULTITOUCH_WIN_8)
-                /*
-                 * Some multitouch screens do not like to be polled for input
-                 * reports. Fortunately, the Win8 spec says that all touches
-                 * should be sent during each report, making the initialization
-                 * of input reports unnecessary.
-                 *
-                 * In addition some touchpads do not behave well if we read
-                 * all feature reports from them. Instead we prevent
-                 * initial report fetching and then selectively fetch each
-                 * report we are interested in.
-                 */
-                hdev->quirks |= HID_QUIRK_NO_INIT_REPORTS;
-
         td = devm_kzalloc(&hdev->dev, sizeof(struct mt_device), GFP_KERNEL);
         if (!td) {
                 dev_err(&hdev->dev, "cannot allocate multitouch data\n");
@@ -1138,6 +1106,39 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
         if (id->vendor == HID_ANY_ID && id->product == HID_ANY_ID)
                 td->serial_maybe = true;
 
+        /*
+         * Store the initial quirk state
+         */
+        td->initial_quirks = hdev->quirks;
+
+        /* This allows the driver to correctly support devices
+         * that emit events over several HID messages.
+         */
+        hdev->quirks |= HID_QUIRK_NO_INPUT_SYNC;
+
+        /*
+         * This allows the driver to handle different input sensors
+         * that emits events through different reports on the same HID
+         * device.
+         */
+        hdev->quirks |= HID_QUIRK_MULTI_INPUT;
+        hdev->quirks |= HID_QUIRK_NO_EMPTY_INPUT;
+
+        /*
+         * Some multitouch screens do not like to be polled for input
+         * reports. Fortunately, the Win8 spec says that all touches
+         * should be sent during each report, making the initialization
+         * of input reports unnecessary. For Win7 devices, well, let's hope
+         * they will still be happy (this is only be a problem if a touch
+         * was already there while probing the device).
+         *
+         * In addition some touchpads do not behave well if we read
+         * all feature reports from them. Instead we prevent
+         * initial report fetching and then selectively fetch each
+         * report we are interested in.
+         */
+        hdev->quirks |= HID_QUIRK_NO_INIT_REPORTS;
+
         ret = hid_parse(hdev);
         if (ret != 0)
                 return ret;
@@ -1206,8 +1207,11 @@ static int mt_resume(struct hid_device *hdev)
 
 static void mt_remove(struct hid_device *hdev)
 {
+        struct mt_device *td = hid_get_drvdata(hdev);
+
         sysfs_remove_group(&hdev->dev.kobj, &mt_attribute_group);
         hid_hw_stop(hdev);
+        hdev->quirks = td->initial_quirks;
 }
 
 /*