Hi Pablo, Adding Stéphane, Henrik and Jiri in CC. On Fri, May 27, 2011 at 17:33, Pablo Cases <pablo.cases@xxxxxxxxxxxx> wrote: > > Hi all, > > I have searched the net and the archives of linux-input for information on how to use the Linux g_hid kernel module on a device and the hid-multitouch kernel module on a host to communicate multitouch events. But unfortunately I can only get single touch working. Excuse my ignorance, I didn't know g_hid existed before your mail. If I understand it well enough, it's an hid emulation from user-space. Are you trying to inject events from a device in user-space to the kernel? If so, I think it would be easier to use uinput. And the funny think was that I'm currently writing a small lib to inject mulitouch events in a uinput device in an easier way. > > Q: Has anyone successfully completed a g_hid <-> hid-multitouch setup? And is there a description somewhere of such setup? I don't think so, hid-multitouch is really new (since 2.6.38, and was not very generic at this time). > Q: Is the Windows 7 multitouch USB HID descriptor the correct one to use also for Linux hid-multitouch? Or is some tweaking necessary? Normally, any valid Windows 7 multitouch USB HID descriptor can be handled by hid-multitouch. But it's more the events that are sent to hid-multitouch that will tell if your device is compatible or not. > > DETAILED DESCRIPTION BELOW > The device is a Linux device that uses g_hid (currently 2.6.37 kernel) and a USB HID Report Descriptor for multitouch using two-touch parallel mode according to Microsoft document http://msdn.microsoft.com/en-us/windows/hardware/gg487437. > > On the host (ubuntu 11.04, 2.6.38 kernel) I register dynamically according to the description at http://lii-enac.fr/en/architecture/linux-input/multitouch-ubuntu-howto.html. Using the events/rdesc files in debugfs on Ubuntu 11.04 I have validated the parsing of the report descriptor and the input reports. This is really a bad idea to use these howto with ubuntu 11.04 ATM. I didn't found the time to update this stuff, and this branch can not be used in ubuntu 11.04 (it contains code for 2.6.35 only, and there were changes in the hid layer after). If you only used the part "How to add your device to hid-multitouch from the user space" without updating your hid module, then it's as if you have'nt done anything (the generic hid module can not autodetect multitouch devices). > > Example multitouch input report from /sys/kernel/debug/hid/0003:xxxx:yyyy.0002/events looks correct: > report (size 14) (numbered) = 05 03 00 a5 12 32 0e 03 01 99 14 32 0e 02 > Digitizers.TipSwitch = 1 > Digitizers.InRange = 1 > Digitizers.ContactID = 0 > GenericDesktop.X = 4773 > GenericDesktop.Y = 3634 > Digitizers.TipSwitch = 1 > Digitizers.InRange = 1 > Digitizers.ContactID = 1 > GenericDesktop.X = 5273 > GenericDesktop.Y = 3634 > Digitizers.ContactCount = 2 > Most of the time, the problematic part comes from the releases. But it's a good start. > The first touch in the report is correctly presented both on Windows and on Ubuntu 11.04 (using ENAC's mtdiag tool with a minor tweak to display data from all devices not just multitouch ones). I can see in the debugfs files that the data for the second touch data is correctly transferred and interpreted (see above), but the mapping to the linux input system seems a bit strange though (see below). My guess is that I have not been correctly registered as a multitouch device. I'm assuming this also because I cannot see any activity from the hid-multitouch module other than it being initialized when I connect my device (probably another reason for the needed tweak in mtdiag above). > > Example mapping from /sys/kernel/debug/hid/0003:xxxx:yyyy.0002/rdesc that does not look entirely correct for the second touch: > Digitizers.TipSwitch ---> Key.Touch > Digitizers.InRange ---> Key.ToolPen > Digitizers.ContactID ---> Absolute.Misc > GenericDesktop.X ---> Absolute.X > GenericDesktop.Y ---> Absolute.Y > Digitizers.TipSwitch ---> Key.Touch > Digitizers.InRange ---> Key.ToolRubber > Digitizers.ContactID ---> Absolute.? > GenericDesktop.X ---> Absolute.Z > GenericDesktop.Y ---> Absolute.Rx This means that your device is handled by the generic usbhid and not hid-multitouch. If you are trying to inject events from the user space, I strongly recommend to use uinput instead. Let me know if you want to have my little uinput-multitouch lib. Cheers, Benjamin > Digitizers.ContactCount ---> Absolute.? > Button.0001 ---> Key.LeftBtn > Button.0002 ---> Key.RightBtn > Button.0003 ---> Key.MiddleBtn > GenericDesktop.X ---> Relative.X > GenericDesktop.Y ---> Relative.Y > GenericDesktop.Wheel ---> Relative.Wheel > > > Regards, > Pablo Cases > > ------------------------- > Pablo Cases, M.Sc. > Development Engineer Software > FlatFrog Laboratories AB > Magistratsvägen 10 > 22643 Lund > Sweden > Tel: +46 708 393816 > Mail: pc@xxxxxxxxxxxx > Web: www.flatfrog.com > -- > To unsubscribe from this list: send the line "unsubscribe linux-input" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
