From: Hartmut Knaack <knaack.h@gmx.de>
To: Benjamin Tissoires <benjamin.tissoires@gmail.com>
Cc: linux-input@vger.kernel.org
Subject: Re: [RFC] enumeration of "composite devices" using v-usb
Date: Sun, 03 Feb 2013 01:03:40 +0100 [thread overview]
Message-ID: <510DA95C.20607@gmx.de> (raw)
In-Reply-To: <CAN+gG=EKTkCBifd1zgriigJObq0PHBNuqgAu9sD=144PRcXtSw@mail.gmail.com>
Benjamin Tissoires schrieb:
> On Fri, Jan 18, 2013 at 5:56 PM, Hartmut Knaack <knaack.h@gmx.de> wrote:
>> Hi,
>> I've built myself a joystick adapter (project website: http://www.hexagons.de/index.php/USB_Joystickadapter), which has the purpose of connecting up to 2 Atari style joysticks (the ones with db9 connectors, found on 80's home computers like C64, Amiga,...) via USB. Current situation is: on Windows XP, 2 joystick devices get created with 2 axis and 2 buttons each (as intended); while on Linux, just one joystick device (/dev/input/js0) gets created, but with 4 axis and 4 buttons.
>> This device provides one interface with one Interrupt-in Endpoint. The division into two joystick devices is done using an HID descriptor [1] with two configurations and the REPORT_ID tag.
>> What I would like to know is, is there a problem in the Linux HID parser, or is its behavior intentional and those composite devices more like a dirty solution around the standards?
> Hi,
>
> well, currently, the HID parser does not split the different reportID
> into several devices. It's a known limitation and we are working on it
> (at least we already saw problems with that), but it will not make it
> in 3.9 I think.
> The solution that works for now is to use several usb interfaces. The
> usb layer splits the different interfaces, so it will give you 2
> different HID devices.
> Oh, and if you want to contribute to split the device in the HID
> parser under Linux, you are welcome as well :)
>
> Cheers,
> Benjamin
Hi,
using the quirk HID_QUIRK_MULTI_INPUT led to the right result: js0 and js1 got created. So, after getting to know a bit about all the probing and parsing, I found a rather simple solution/workaround. In hid-input.c, function hidinput_connect, replace:
1251 <http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=blob;f=drivers/hid/hid-input.c;h=21b196c394b197d222e0d1f58ac52f37d65b3e5d;hb=HEAD#l1251>
1252 <http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=blob;f=drivers/hid/hid-input.c;h=21b196c394b197d222e0d1f58ac52f37d65b3e5d;hb=HEAD#l1252> if (hid->quirks & HID_QUIRK_MULTI_INPUT) {
1253 <http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=blob;f=drivers/hid/hid-input.c;h=21b196c394b197d222e0d1f58ac52f37d65b3e5d;hb=HEAD#l1253> /* This will leave hidinput NULL, so that it
with:
1251 <http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=blob;f=drivers/hid/hid-input.c;h=21b196c394b197d222e0d1f58ac52f37d65b3e5d;hb=HEAD#l1251>
1252 <http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=blob;f=drivers/hid/hid-input.c;h=21b196c394b197d222e0d1f58ac52f37d65b3e5d;hb=HEAD#l1252> if (hid->quirks & HID_QUIRK_MULTI_INPUT || report->id) {
1253 <http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=blob;f=drivers/hid/hid-input.c;h=21b196c394b197d222e0d1f58ac52f37d65b3e5d;hb=HEAD#l1253> /* This will leave hidinput NULL, so that it
The parser makes sure that, if the HID Report Descriptor contains a definition for reportID, it is not zero.
Is this attempt OK for you, or do you see any problems? And is HID_QUIRK_MULTI_INPUT still needed in this case?
Thanks
Hartmut
>> Thanks
>>
>> Hartmut Knaack
>>
>> [1]
>> char usbHidReportDescriptor[102] PROGMEM = {
>>
>> // Joystick Port 1
>>
>> 0x05, 0x01, // USAGE_PAGE (Generic Desktop)
>> 0x09, 0x04, // USAGE (Joystick)
>> 0xa1, 0x01, // COLLECTION (Application)
>> 0x85, 0x01, // REPORT_ID (1)
>> 0x09, 0x01, // USAGE (Pointer)
>> 0xa1, 0x00, // COLLECTION (Physical)
>> 0x09, 0x30, // USAGE (X)
>> 0x09, 0x31, // USAGE (Y)
>> 0x15, 0x00, // LOGICAL_MINIMUM (0)
>> 0x26, 0xff, 0x00, // LOGICAL_MAXIMUM (255)
>> 0x75, 0x08, // REPORT_SIZE (8)
>> 0x95, 0x02, // REPORT_COUNT (2)
>> 0x81, 0x02, // INPUT (Data,Var,Abs)
>> 0xc0, // END_COLLECTION
>> 0x05, 0x09, // USAGE_PAGE (Button)
>> 0x19, 0x01, // USAGE_MINIMUM (Button 1)
>> 0x29, 0x02, // USAGE_MAXIMUM (Button 2)
>> 0x15, 0x00, // LOGICAL_MINIMUM (0)
>> 0x25, 0x01, // LOGICAL_MAXIMUM (1)
>> 0x75, 0x01, // REPORT_SIZE (1)
>> 0x95, 0x02, // REPORT_COUNT (2)
>> 0x81, 0x02, // INPUT (Data,Var,Abs)
>> 0x75, 0x06, // REPORT_SIZE (6)
>> 0x95, 0x01, // REPORT_COUNT (1)
>> 0x81, 0x03, // INPUT (Constant,Var,Abs)
>> 0xc0, // END_COLLECTION
>>
>> // Joystick Port 2
>>
>> 0x05, 0x01, // USAGE_PAGE (Generic Desktop)
>> 0x09, 0x04, // USAGE (Joystick)
>> 0xa1, 0x01, // COLLECTION (Application)
>> 0x85, 0x02, // REPORT_ID (2)
>> 0x09, 0x01, // USAGE (Pointer)
>> 0xa1, 0x00, // COLLECTION (Physical)
>> 0x09, 0x30, // USAGE (X)
>> 0x09, 0x31, // USAGE (Y)
>> 0x15, 0x00, // LOGICAL_MINIMUM (0)
>> 0x26, 0xff, 0x00, // LOGICAL_MAXIMUM (255)
>> 0x75, 0x08, // REPORT_SIZE (8)
>> 0x95, 0x02, // REPORT_COUNT (2)
>> 0x81, 0x02, // INPUT (Data,Var,Abs)
>> 0xc0, // END_COLLECTION
>> 0x05, 0x09, // USAGE_PAGE (Button)
>> 0x19, 0x01, // USAGE_MINIMUM (Button 1)
>> 0x29, 0x02, // USAGE_MAXIMUM (Button 2)
>> 0x15, 0x00, // LOGICAL_MINIMUM (0)
>> 0x25, 0x01, // LOGICAL_MAXIMUM (1)
>> 0x75, 0x01, // REPORT_SIZE (1)
>> 0x95, 0x02, // REPORT_COUNT (2)
>> 0x81, 0x02, // INPUT (Data,Var,Abs)
>> 0x75, 0x06, // REPORT_SIZE (6)
>> 0x95, 0x01, // REPORT_COUNT (1)
>> 0x81, 0x03, // INPUT (Constant,Var,Abs)
>> 0xc0 // END_COLLECTION
>> };
>> --
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next prev parent reply other threads:[~2013-02-03 0:03 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-18 22:56 [RFC] enumeration of "composite devices" using v-usb Hartmut Knaack
2013-01-21 15:45 ` Benjamin Tissoires
2013-01-23 18:22 ` Benjamin Tissoires
2013-01-24 22:48 ` Hartmut Knaack
2013-02-03 0:03 ` Hartmut Knaack [this message]
2013-02-03 10:41 ` Benjamin Tissoires
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