Police in the US at least are routinely acquitted of using excessive force against black people, even when there's clear video evidence of them doing it, going back to Rodney King, and eyewitness evidence going back even further. So when I say they have to be held responsible, I mean by the courts.

Well the court has clearly deemed the use of force to not be excessive, or have found another way to dismiss the case. What change can we make here? Put all cases before a jury? That might work.

You can ban certain maneuvers like kneeling on someone's neck or choking people, for example, which a number of dept's have done.
I'm going to go out on a limb and say that change is coming.

You can also train them to de-escalate situations and use force only as a last resort. Too many of them use it as a first resort.
Do you have evidence that the police are not trained to deescalate?

But mostly, the first point ties to the second. If you show them that if they get out of line it will have serious consequences for them personally, including possible jail time, they'll get the message pretty quick.

I'm pretty sure the first thing I said on this matter was "You know what cops fear more than riots? Jail."

I agree that cops who kill without legal justification should go to jail. That would have an impact. But that alone is not going to change the systematic racism and the division of the masses. It perhaps simply makes events like these riots less likely to happen, which is probably good for the system, because the ideal for them is to surely keep the masses just oppressed enough that they don't complain about it.