Hi, resending this once again, hoping it wouldn't contain any HTML and wouldn't be filtered by LKML. 03.03.2021 13:11, Nikolai Kostrigin пишет: > Hi, > > 25.02.2021 12:38, Wolfram Sang пишет: >> Hi, >> >>> I had a preliminary discussion with Benjamin Tissoires and according to >>> our agreement I repost it for wider audience. >>> Blacklisting the device was decided to be a bad idea. >>> But actually I managed to get touchpad totally operational via SMBus >>> using a following hack: >>> >>> providing a parameter to i2c_i801 driver: >>> >>> modprobe i2c_i801 disable_features=0x2 (i.e. disable the block buffer). >> So, from an I2C perspective, there are two things to mention here: >> >> a) I am in the process of extending the I2C core to allow block >> transfers > 32 byte. This is a slow process, though, because we need to >> pay attention to not break userspace ABI. If this is done *and* the i801 >> driver supports length > 32 bytes, too, then it would work natively. If >> the i801 can do this, this is a question for Jean Delvare. >> >> b) I don't know Elantech HW but there are devices out there which allow >> configuration for the block size. Something like a bit specifying if >> block transfers > 32 are allowed. Or the SMBus version to support. Block >> transfers > 32 are SMBus 3.0+ only. If your HW does not have that, >> disabling SMBus is an option, too. Disabling it in the i801 driver is >> too much of a hammer, I'd say. >> >> Hope this helps! Happy hacking, >> >> Wolfram > Thank you for the information, Wolfram! > > Finally it turned out that the solution was near me from the very > beginning, but I failed to check mainline code at that moment (which is > now 5.11). > Happily Jingle Wu has pointed me to a couple of patches of his > (co-authored by Dmitry Torokhov): > > https://git.kernel.org/pub/scm/linux/kernel/git/dtor/input.git/commit/?h=next&id=056115daede8d01f71732bc7d778fb85acee8eb6 > > https://git.kernel.org/pub/scm/linux/kernel/git/dtor/input.git/commit/?h=next&id=e4c9062717feda88900b566463228d1c4910af6d > > I applied those to 5.10.17 and trackpoint works like a charm. > So I guess theese patches are worth being backported to the longterm > 5.10 branch. > I'm really sorry for the noise. > -- Best regards, Nikolai Kostrigin
