On Wed, Aug 19, 2015 at 5:27 PM, Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> wrote: > On Wed, Aug 19, 2015 at 09:52:00AM -0400, Benjamin Tissoires wrote: >> On Tue, Aug 18, 2015 at 3:06 PM, Benjamin Tissoires >> <benjamin.tissoires@xxxxxxxxx> wrote: >> > Hi Nick, >> > >> > thanks for the report. >> > >> > On Mon, Aug 17, 2015 at 10:31 PM, Nick Bowler <nbowler@xxxxxxxxxx> wrote: >> >> Hi, >> >> >> >> I'm not sure if this is actually a Linux issue but figured I'd at least >> >> report it here to start... >> >> >> >> I have a Lenovo Thinkpad X250, with the newfangled trackpoint buttons. >> >> I have a problem with missing button press or release events: sometimes >> >> pressing a button has no effect, and sometimes releasing a button has no >> >> effect (the latter is especially annoying, as the button remains depressed >> >> as far as any applications are concerned). >> >> >> >> After some testing, the problem apparently depends on the position of my >> >> hands over the touchpad. I can reliably reproduce it as follows: place >> >> two fingers on the touchpad, then press the button repeatedly. Watching >> >> with evtest, several events (could be either press or release) will >> >> simply be missin, although the kernel never does anything weird like >> >> send two release events in a row. There are no problems if there are >> >> 0 or 1 fingers on the touchpad. >> >> >> >> My current kernel version is 4.1.6, although the problem occurs in all >> >> versions that I tried. >> >> >> >> Here is the evtest result from placing two fingers on the touchpad, then >> >> pressing the left trackpoint button 10 times, counting 1 second between >> >> each press. As you can see, only 3 presses and 3 release events total >> >> were sent by the kernel, sometimes with many physical button presses >> >> between the press and its corresponding release: >> > >> > OK, so this is definitively weird. My first idea would be a firmware >> > problem. I have asked Chandler to reproduce it on his t450 and see if >> > we observe it on our laptops too. >> >> Update on this one : Chandler reproduced it on the t450, so it's >> likely that all of these sensors are affected. It is still unclear if >> it is a firmware bug or a driver problem, but the chances are huge >> that this is a firmware bug. Anyway, that's one more reason to push >> towards RMI4 over SMBus for these sensors: the bug is not present with >> this protocol :) > > By the way, how are we going to handle Trackpoint (PS/2 device) with > touchpads in RMI4 mode? I do not recall anything in RMI4 spec, but I > looked at it quite some time ago. > Yes, there is nothing public in the spec for the RMI4 PS/2 pass-through mode. With a little help of Synaptics, Chandler implemented it (it's function 03): https://github.com/bentiss/linux/commit/b0cea92f56db9fc521a3ffaad534d91ef33466c8 This might not be the last version I have on my laptop, but it should be close enough (if you also add the reporting of the extra buttons that are sent through the GPIO function - 30). Basically, I am running this code on a day to day basis, and we have spotted most of the bugs now I think. It is stable and works better than the PS/2 implementation because we don't have the bugs inherent to the "report 2 slots but 5 actually". Cheers, Benjamin PS: looks like Chandler beat me at answering -- 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
