Hi, On 10/03/2014 12:05 PM, Pali Rohár wrote: > On Friday 03 October 2014 11:55:52 Hans de Goede wrote: >> Hi, >> >> On 10/03/2014 11:43 AM, Pali Rohár wrote: >>> For unknown reasons linux psmouse alps driver sometimes >>> receive totally invalid packet sequences on Dell Latitude >>> laptops. According to ALPS HW engineers these invalid >>> packets do not come from ALPS devices. So it looks like bug >>> in BIOS and EC incorrectly split keyboard and touchpad PS/2 >>> data when laptops are under heavy loads (big I/O together >>> with powersave governor, running on battery). >>> >>> There are sequences of invalid packets (which are dropeed) >>> and some sequences which look like valid. But these valid >>> packets cause random trackstick button pressing, random >>> cursor moving/jumping and in these condition it is not >>> possible to use ALPS device (trackstick+touchpad). >>> >>> To prevent random button press and random cursor jumps >>> immediately reset ALPS device after first invalid packet. >>> This will cause that touchpad and trackstick will not >>> respond for one or two seconds and it better then random >>> cursor jumps. >> >> This one probably should have: >> >> Bug: https://bugzilla.redhat.com/show_bug.cgi?id=1145954 >> > > Yes, in that bug is described same problem as on my E6440. > >> And you may want to add Bug: tags to the relevant patches for >> the launchpad issues too. >> OK, so lets just reference the RH bug then, and leave the others out. > > I just added links to famous ALPS bugs which looks like that one > which I have on my E6440. But I'm not sure if my patches will > resolve these problems on other machines too. > >> While on the topic of tags, once we've agreed upon the return >> value to use for the 2nd patch, can you please resend with a >> "Cc: stable@xxxxxxxxxxxxxxx" added to all 3 patches? >> > > I would like if somebody else can test patches on other machines > with ALPS devices. Specially this third if it does not break > something else. In my experience with ALPS devices, they normally never cause PSMOUSE_BAD_DATA errors, so I would not worry about regressing because of that. > Note that this third patch does not fixing problem correctly with > jumping & clicking. It just immediately reset ps/2 device if it > receive invalid packages. So it only try to prevent jumping & > clicking. I understand, but that seems to be the best we can do for now. > On my E6440 machine it somehow working. When driver > doing ps/2 reset keyboard, touchpad and trackstick not > responding. Right, but I would expect that to be for only a short period of time, or does the whole reset take a significant amount of time ? > I think it is better then having random clicks but > somebody else really should try and test patches how it will work > on other machines. > > Proper fix would be to understand why invalid packets are > received and try to force buggy component to not send these > invalid packets. Regards, Hans -- 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
