Hi Terry,
On Fri, Aug 31, 2018 at 7:48 PM Junge, Terry Terry.Junge@plantronics.com wrote:
For what it's worth the Report Descriptor is a little questionable which could be causing the collection to split in two
-----Original Message----- From: linux-input-owner@vger.kernel.org [mailto:linux-input- owner@vger.kernel.org] On Behalf Of Benjamin Tissoires Sent: Friday, August 31, 2018 2:36 AM To: Jiri Kosina jikos@kernel.org; Dmitry Torokhov dmitry.torokhov@gmail.com Cc: linux-input@vger.kernel.org; linux-kernel@vger.kernel.org; Benjamin Tissoires benjamin.tissoires@redhat.com; stable@vger.kernel.org Subject: [PATCH] Partially revert "HID: generic: create one input report per application type"
This partially reverts commit f07b3c1da92db108662f99417a212fc1eddc44d1.
It looks like some mice are not correctly treated by HID_QUIRK_INPUT_PER_APP. Those mice have the following report descriptor:
0x05, 0x01, // Usage Page (Generic Desktop) 0 0x09, 0x02, // Usage (Mouse) 2 0xa1, 0x01, // Collection (Application) 4 0x85, 0x01, // Report ID (1) 6 0x09, 0x01, // Usage (Pointer) 8
This physical collection is associated with Generic Desktop:Pointer (0x0001:0x0001)
0xa1, 0x00, // Collection (Physical) 10 0x95, 0x05, // Report Count (5) 12 0x75, 0x01, // Report Size (1) 14 0x05, 0x09, // Usage Page (Button) 16
We are now in the Button page
0x19, 0x01, // Usage Minimum (1) 18 0x29, 0x05, // Usage Maximum (5) 20 0x15, 0x00, // Logical Minimum (0) 22 0x25, 0x01, // Logical Maximum (1) 24 0x81, 0x02, // Input (Data,Var,Abs) 26 ... 0xc0, // End Collection 57 0x85, 0x02, // Report ID (2) 58 0x09, 0x01, // Usage (Consumer Control) 60
This physical collection is associated with Button:Button 1 (0x0009:0x0001) not Generic Desktop:Pointer (0x0001:0x0001)
0xa1, 0x00, // Collection (Physical) 62 0x75, 0x0c, // Report Size (12) 64 0x95, 0x02, // Report Count (2) 66 0x05, 0x01, // Usage Page (Generic Desktop) 68
Now we're back in the Generic Desktop page
You are missing one bit in the HID specification. The report descriptor is both a stack and a machine with states. The 'usage page' can be considered as a 'register' that needs to be associated to the 'usage' to provide the final usage. For example, Usage Page 0x01 (Generic Desktop) plus Usage 0x30 gives you the "X" usage. While Usage Page 0x0d (digitizer) plus the same Usage 0x30 gives you the "Tip Pressure".
So here, there is nothing wrong.
The stack part concerns the collections. You open a collection type (physical, or application), and you can close it.
So here, the problem is that the 2 reports with Ids 1 and 2 are part of the same application collection "mouse" and should be tied to the same input device (at least that is how I thought of the code). Unfortunately, the bug makes that these 2 reports each have an input node, and this is where things start to mess up.
Cheers, Benjamin
0x09, 0x30, // Usage (X) 70 0x09, 0x31, // Usage (Y) 72 0x16, 0x01, 0xf8, // Logical Minimum (-2047) 74 0x26, 0xff, 0x07, // Logical Maximum (2047) 77 0x81, 0x06, // Input (Data,Var,Rel) 80 0xc0, // End Collection 82 0xc0, // End Collection 83 ...