(ioctl(ts->fd, EVIOCGVERSION, &version) returns me -1, why??

webquinty · 07-07-2008, 04:46 AM

Hello,

(ioctl(ts->fd, EVIOCGVERSION, &version)

I would like to known why ioctl retuns me -1.
I understand that this fuction returns me version of drivers of device.
is it correct or no?
And if the answer is yes, what is the problem, driver return me more information????

Best regards
John Martin

webquinty · 07-07-2008, 06:04 AM

Well , I have found this

(ioctl(ts->fd, EVIOCGVERSION, &version)) returns me -1

but this other

(ioctl(ts->fd, HIDIOCGVERSION, &version)) returns me 0

In my kernel source, touchscreen device is configurate as HID_USB device.

is there any difference between EVIOCGVERSION and HIDIOCGVERSION???

Best regards

pinniped · 07-07-2008, 06:15 AM

Quote:

Originally Posted by webquinty

is there any difference between EVIOCGVERSION and HIDIOCGVERSION???

The supported IOCTLs depend on the device and the driver. If the return value is '-1' you should check the value of 'errno' for more information on what went wrong.

webquinty · 07-07-2008, 07:54 AM

Quote:

Originally Posted by pinniped

The supported IOCTLs depend on the device and the driver. If the return value is '-1' you should check the value of 'errno' for more information on what went wrong.

Hello,

well, I made some changes to obtain errno when ioctl returns me -1

errno = 25 --> ENOTTTY. This almost always is the result of an ioctl() call applied to an inappropriate device type.

As I understand, this error is normal, because my device is not a input charcater, it is a HID device, then this is the reason of error, I understand.

Well, now I need to known if I can use TSLIB with this device, but this question is not for this forum.

thank you very much pinniped.

Best regards