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. Thanks. -- Dmitry -- 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
