From: "Blaž Hrastnik" <blaz@mxxn.io>
To: unlisted-recipients:; (no To-header on input)
Cc: "Blaž Hrastnik" <blaz@mxxn.io>, "Jiri Kosina" <jikos@kernel.org>,
"Benjamin Tissoires" <benjamin.tissoires@redhat.com>,
linux-input@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] HID: Improve Windows Precision Touchpad detection.
Date: Wed, 6 Nov 2019 20:02:46 +0900 [thread overview]
Message-ID: <20191106110246.70937-1-blaz@mxxn.io> (raw)
Per Microsoft spec, usage 0xC5 (page 0xFF) returns a blob containing
data used to verify the touchpad as a Windows Precision Touchpad.
0x85, REPORTID_PTPHQA, // REPORT_ID (PTPHQA)
0x09, 0xC5, // USAGE (Vendor Usage 0xC5)
0x15, 0x00, // LOGICAL_MINIMUM (0)
0x26, 0xff, 0x00, // LOGICAL_MAXIMUM (0xff)
0x75, 0x08, // REPORT_SIZE (8)
0x96, 0x00, 0x01, // REPORT_COUNT (0x100 (256))
0xb1, 0x02, // FEATURE (Data,Var,Abs)
However, some devices, namely Microsoft's Surface line of products
instead implement a "segmented device certification report" (usage 0xC6)
which returns the same report, but in smaller chunks.
0x06, 0x00, 0xff, // USAGE_PAGE (Vendor Defined)
0x85, REPORTID_PTPHQA, // REPORT_ID (PTPHQA)
0x09, 0xC6, // USAGE (Vendor usage for segment #)
0x25, 0x08, // LOGICAL_MAXIMUM (8)
0x75, 0x08, // REPORT_SIZE (8)
0x95, 0x01, // REPORT_COUNT (1)
0xb1, 0x02, // FEATURE (Data,Var,Abs)
0x09, 0xC7, // USAGE (Vendor Usage)
0x26, 0xff, 0x00, // LOGICAL_MAXIMUM (0xff)
0x95, 0x20, // REPORT_COUNT (32)
0xb1, 0x02, // FEATURE (Data,Var,Abs)
By expanding Win8 touchpad detection to also look for the segmented
report, all Surface touchpads are now properly recognized by
hid-multitouch.
Signed-off-by: Blaž Hrastnik <blaz@mxxn.io>
---
drivers/hid/hid-core.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 63fdbf09b044..2af597cd5d65 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -742,6 +742,10 @@ static void hid_scan_feature_usage(struct hid_parser *parser, u32 usage)
if (usage == 0xff0000c5 && parser->global.report_count == 256 &&
parser->global.report_size == 8)
parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8;
+
+ if (usage == 0xff0000c6 && parser->global.report_count == 1 &&
+ parser->global.report_size == 8)
+ parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8;
}
static void hid_scan_collection(struct hid_parser *parser, unsigned type)
--
2.23.0
next reply other threads:[~2019-11-06 11:03 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-06 11:02 Blaž Hrastnik [this message]
2019-11-07 8:48 ` [PATCH] HID: Improve Windows Precision Touchpad detection Benjamin Tissoires
2019-11-07 9:06 ` Blaž Hrastnik
2019-11-18 10:04 ` Benjamin Tissoires
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