(In reply to lei.pero from comment #18)
> I didn't know that about modesetting driver, anyway, even with
> LIBGL_DRI3_DISABLE=1 same thing happens.

Maybe chromium doesn't pass on the environment variable to its GPU helper
process, or maybe there was still a chromium process around.

> I don't how to disable tripple buffering to test it and if it's possible,

Only by changing the code,
mesa/src/loader/loader_dri3_helper.c:dri3_update_num_back(). E.g. set num_back
= 1 in the else case.