Template Version: @(#)sac_nextcase 1.68 02/23/09 SMI
This information is Copyright 2009 Sun Microsystems
1. Introduction
1.1. Project/Component Working Name:
HIDIOCKM[GS]DIRECT ioctls for the USB HID driver
1.2. Name of Document Author/Supplier:
Author: Aaron Zang
1.3 Date of This Document:
31 May, 2009
4. Technical Description
HIDIOCKM[GS]DIRECT ioctls for the USB HID driver
1. Introduction
1.1 Project/Component Working Name:
HIDIOCKM[GS]DIRECT ioctls for the USB HID driver
1.2 Name of Document Author/Supplier:
Aaron Zang
1.3 Date of This Document:
05/25/09
2. Background
The USB HID STREAMS driver exports 2 device nodes for each USB keyboard/mouse
device instance. One is for the internal use of kernel under the name of
"internal-keyboard" or "internal-mouse". The other is for the external use
of user land applications under the name of "keyboard" or "mouse".
If a keyboard/mouse device node is opened, a stream is established for the
I/O of that node.
The relationship of the internal node (stream), external node (stream),
virtual keyboard mouse, console and applications are shown by the below
diagram.
"/dev/console" "/dev/kbd" "/dev/usb/hid%d"
"/dev/vt/%d" "/dev/mouse"
| | | Uesr Land
----------+---------+-----------+--------------
| | | Kernel
+---------+ | |
| console | | |
+----+----+ | |
| | |
+----+---------+--+ |
| virtual keyboard| |
| mouse | |
+----------+------+ | <--- (HID external stream)
| |
| |
+---------+ |
| |
(HID interal stream) ---> | |
+--------+--+
| HID |
+-----------+
>From the diagram we can see, the internal stream is used by console.
The external stream is used by applications which open the "/dev/usb/hid%d"
device nodes directly.
Since XOrg 1.5, the XOrg server opens hid deivces (/dev/usb/hid%d)
by default instead of "/dev/kbd" or "/dev/mouse". Even before XOrg 1.5, it
still can be configured to open the hid devices directly.
3. Problem
When both of the internal and external node are opened, 2 streams are
set up for both of them. But only one can get the the input from the
hardware at one time. The internal stream usually gets the input first
since the conskbd (virtual keyboard) driver opens the internal node when
system boots.
The current solution is that the input goes to the external stream when
the external node is opened by some application, and the input gets switched
back to the internal stream when the external stream was disassembled.
When working on the XOrg support for Solaris Virtual Console, the project
team found the console would lose input if switched back from one of the
X sessions. It is because the XOrg server still opens the HID external
node which causes the input still direct to the external stream.
4. Proposal
To solve the above problem, two new HID ioctls are introduced:
Exported Interface Stability Comments
Name Classification
------------------ -------------- ----------
HIDIOCKMGDIRECT Committed See hid.7D
HIDIOCKMSDIRECT Committed See hid.7D
HIDIOCKMGDIRECT is used to get the information of which stream gets the
input at the moment. A return value of 0 means the internal stream gets
the input, and a return value of 1 means the external stream gets the input.
HIDIOCKMSDIRECT is used to set the directing of the streams. An argument
of 0 directs the input to the internal stream and an argument of 1 directs
the input to the external stream.
The existing behavior remains by the lasted opened stream gets the input
automatically.
5. References
PSARC/2006/591 Virtual Console
PSARC/2004/717 Virtual Keyboard/Mouse
hid(7D)
6. Resources and Schedule
6.4. Steering Committee requested information
6.4.1. Consolidation C-team Name:
ON
6.5. ARC review type: FastTrack
6.6. ARC Exposure: open
