Hi Dmitry, On Fri, Mar 20, 2015 at 09:39:55AM -0700, Dmitry Torokhov wrote: > Hi Ulrik, > > On Thu, Mar 19, 2015 at 11:05:46PM +0100, ulrik.debie-os@xxxxxxxxx wrote: > > Hi all, > > > > I looked at the bugzilla bugreport on > > https://bugzilla.kernel.org/show_bug.cgi?id=84491 > > "Elantech touchpad does not work on Asus TransformerBook Flip 500" > > > > There are problems reported on two variants: > > Asus TransformerBook Flip TP500LN > > Asus TP500LN > > > > George (in CC:) helped me to investigate on his hardware what happened > > by trying a few patches and reporting what happens. > > > > It seems that the absolute mode setting somehow gets cancelled after the > > elantech drivers initializes. This results in relative motion packets > > coming in, elantech driver not recognizing them and consequentially > > "lost sync at byte 6" messages. > > > > When one, after the psmouse driver is loaded, does the following: > > echo 1 > /sys/devices/platform/i8042/serio4/reg_07 > > ,the touchpad will work like a charm until suspend2ram. After a > > suspend2ram, another echo is required. > > > > This exact same value is written during initialization of v4 hardware. > > As a test, I even read it back in elantech_set_absolute_mode after > > writing and at that moment in the driver the value 1 is read. > > > > But when one performs the read later on the commandline of reg_07, value > > 0 is read, so probably for a reason unknown to me, the value goes to > > 0 because of some timeout or serio communiation. > > > > I also tried putting elantech_set_input_params call in front of > > elantech_set_absolute_mode, but that didn't help either. > > > > Also the suspend2ram seems to result in the same thing. > > > > Anyone an idea why this reg_07 1 value could become a 0 between the time > > the function elantech_set_absolute_mode during loading of the psmouse > > module and the time when reading the value from sysfs from the > > command line ? > > Hmm, so after Elantech code has done with the init you see the correct > value in r7? Psmouse driver does [re]set scale, rate and resolution > after protocol has been initialized, maybe that confuses Elantech in the > same fashion as it does Focaltech? Indeed, this time it is specifically the set_rate that resets the value of reg_07 to 0, resulting in the disabling of the absolute mode. I made a patch on kernel v3.16 that solves the problem and will send it out in like an hour after a final check if it also compiles on kernel v3.19. (The person that tested it is on v3.16 kernel). > > Thanks. > > -- > Dmitry Thanks for once again your valuable input, Ulrik -- 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
