Support event mode for drivers
Current implementation forces poll loop every one second or so,
this consume CPU and power.
This changeset adds the ability for a driver to provide file
descriptor for event handling, removing the need to poll.
Only Linux USB interface was modified to use this new interface.
All other environments will fall-back into the poll mode.
New driver methods:
before_command
Executed before command, makes it easy to remove event capture.
after_command
Execute after command, makes it easy to add event capture.
get_eventfd
Get an event fd out of the driver, if unsupported -1 should
be returned, this fall-back into the poll mode.
event
Event method to call with th evntfd is signaled.
before_command
Execute whatever needed before executing a command. Useful
if driver need to turn off event capture.
after_command
Execute whatever needed before blocking. Useful if driver
need to turn on event capture.
New device methods:
get_eventfd
Gets eventfd if available.
New USB methods:
ifd_usb_get_eventfd
Get event fd to poll for events.
ifd_usb_capture_event
None blocking capture.
New CT socket methods:
error
Called with POLLERR is received.
New configuration file options:
force_poll
Force polling, default is true (as correct behavior),
until Linux kernel will resolve its issues.
New command-line options:
ifdhandler -p
Force polling.
Linux specific notes:
This enable safe detection of device removal and allow USB drivers
to stop polling device, even if they do not have interrupt interface.
As OpenCT uses /dev/bus/usb namespace if exists, and this feature worked
only on usbfs prior to linux-2.6.28, it will not work with older kernels.
linux-2.6.28 has a bug that cause the signal not to be sent if kernel
is configured without CONFIG_USB_DEVICEFS, see [1].
linux-2.6.29 is expected to solve this issue.
Even if ccid driver works correctly, as it uses interrupt endpoint,
by default polling will be forced.
[1] http://marc.info/?t=123075926900001&r=1&w=2
M src/ifd/ifdhandler.c
M src/ifd/utils.c
M src/ifd/process.c
M src/ifd/sys-osx.c
M src/ifd/sys-null.c
M src/ifd/device.c
M src/ifd/internal.h
M src/ifd/usb.c
M src/ifd/reader.c
M src/ifd/sys-linux.c
M src/ifd/sys-bsd.c
M src/ifd/sys-solaris.c
M src/ifd/sys-sunray.c
M src/include/openct/driver.h
M src/include/openct/device.h
M src/include/openct/ifd.h
M src/include/openct/socket.h
M src/ct/mainloop.c
M etc/openct.conf.in
