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
