Re: uinput on headless system ...

[Roberto Alejandro Espi Munoz <raespi@icid.cu>]

Well yes ... the code I posted is actually part of a TCP server client 
connection.  One part of the code gets executed up to the point you 
mentioned.  The part where the keys get sent only executes when 
receiving the network command, so yes, there is a time lapse between one 
part and the other.

On 01/14/2016 09:27 AM, Benjamin Tissoires wrote:
> On Thu, Jan 14, 2016 at 3:05 PM, Roberto Alejandro Espi Munoz
> <raespi@icid.cu> wrote:
>> Yes the uinput driver is compiled as a module and loaded before running the
>> test app that I have (double checked with modprobe and lsmod).  The same
>> code has been compiled for my laptop and everything loads and works fine
>> when sending events to the input subsystem.   I mentioned the physical
>> keyboard issue because that's what made it work: SCENARIO1 the headless
>> motherboard starts without a keyboard and both the module and the app loads
>> but no events get injected and the problem occurs when writing to the
>> /dev/uinput device, SCENARIO2 I connect a physical keyboard and all goes
>> well. I looked at the libevdev before and sinced my code ended up working on
>> my laptop I discarded the library.  I saw the libevdev-uinput.c you
>> recommended, I think I'm following the same rationale.
>>
>> Thanks for the replies ...
>>
>> This is the code I'm using that fails at the end when writing to the
>> /dev/uinput device:
>>
>>      int uinputDev;
>>      struct uinput_user_dev device;
>>      memset(&device, 0, sizeof device);
>>
>>      uinputDev = open("/dev/uinput",O_WRONLY | O_NONBLOCK);
>>          strcpy(device.name,"test remote");
>>
>>          device.id.bustype=BUS_USB;
>>          device.id.vendor=1;
>>          device.id.product=1;
>>          device.id.version=1;
>>
>>
>>          if (write(uinputDev,&device,sizeof(device)) != sizeof(device))
>>          {
>>              fprintf(stderr, "error setup\n");
>>          }
>>          if (ioctl(uinputDev,UI_SET_EVBIT,EV_KEY) < 0)
>>              fprintf(stderr, "error evbit key\n");
>>
>>          if (ioctl(uinputDev,UI_SET_KEYBIT, KEY_LEFT) < 0)
>>              fprintf(stderr, "error evbit key\n");
>>
>>          if (ioctl(uinputDev,UI_SET_KEYBIT, KEY_UP) < 0)
>>              fprintf(stderr, "error evbit key\n");
>>
>>          if (ioctl(uinputDev,UI_SET_KEYBIT, KEY_DOWN) < 0)
>>              fprintf(stderr, "error evbit key\n");
>>
>>          if (ioctl(uinputDev,UI_SET_KEYBIT, KEY_RIGHT) < 0)
>>              fprintf(stderr, "error evbit key\n");
>>
>>          if (ioctl(uinputDev,UI_SET_KEYBIT, KEY_ENTER) < 0)
>>              fprintf(stderr, "error evbit key\n");
>>
>>          if (ioctl(uinputDev,UI_DEV_CREATE) < 0)
>>          {
>>              fprintf(stderr, "error create\n");
>>          }
>>
>>       struct input_event event;
>>
> Just to be sure, is there any sleep here or way to ensure your
> motherboard actually opened the device here?
> If not, you might simply send the events too early, when nobody reads
> them, and thus you think you did not receive them.
>
> Cheers,
> Benjamin
>
>>      memset(&event, 0, sizeof(event));
>>      event.type = EV_KEY;
>>      event.code = KEY_UP;
>>      event.value = 1;
>>      gettimeofday(&event.time,NULL);
>>
>>      if (write( uinputDev, &event, sizeof(struct input_event)) != sizeof(
>> struct input_event) ) {
>>          fprintf(stderr, "Error on send_event");
>>          return -1;
>>      }
>>
>>      memset(&event, 0, sizeof(event));
>>      event.type = EV_KEY;
>>      event.code = KEY_UP;
>>      event.value = 0;
>>      gettimeofday(&event.time,NULL);
>>
>>      if (write( uinputDev, &event, sizeof(struct input_event)) != sizeof(
>> struct input_event) ) {
>>          fprintf(stderr, "Error on send_event");
>>          return -1;
>>      }
>>
>> On 01/14/2016 12:08 AM, Benjamin Tissoires wrote:
>>> Hi Roberto,
>>>
>>> On Wed, Jan 13, 2016 at 11:21 PM, Dmitry Torokhov
>>> <dmitry.torokhov@gmail.com> wrote:
>>>> Hi Roberto,
>>>>
>>>> On Wed, Jan 13, 2016 at 09:19:39AM -0500, Roberto Alejandro Espi Munoz
>>>> wrote:
>>>>> Hello ... I've been searching around the web for a specific mailing
>>>>> list for the uinput driver but couldn't find any.  I managed to
>>>>> create an example app that injects keyboard events to the running
>>>>> linux kernel succesfully when I have a keyboard attached to the
>>>>> computer.  However if I run it on a keyboardless machine, like a
>>>>> standalone motherboard, the uinput device fails to open.
>>>> uinput driver does not depend on presence of a physical keyboard. I'd
>>>> start looking whether uinput module is enabled on your headless box and
>>>> if it is a module verify that it is loaded.
>>>>
>>> As Dmitry said, uinput is independent of any attached hardware.
>>> You might want to see how we managed to create new devices through
>>> uinput by looking at libevdev[1] (see libevdev/libevdev-uinput.c).
>>>
>>> You might actually also want to use libevdev instead of manually doing
>>> the ioctls and processing of all the small things :)
>>>
>>> Cheers,
>>> Benjamin
>>>
>>> [1] http://www.freedesktop.org/wiki/Software/libevdev/
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>>
>>
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