On Mon, Dec 1, 2014 at 3:38 PM, Terje Bergström <[email protected]> wrote: > On 29.11.2014 10:44, Alexandre Courbot wrote: >> On Fri, Nov 28, 2014 at 9:09 PM, Roy Spliet <[email protected]> wrote: >>> I'm not sure if I completely understand your reply, so forgive me if I am >>> stating some obvious things: >>> The reason why I brought this up is because, the way I see it, DTS is the >>> replacement for (V)BIOS on ARM platforms, giving a set of parameters that >>> drivers (nouveau) can use for that particular instance (the Tegra K1 SoC) of >>> some more generic IP (gk20a). All the other devices nouveau supports have a >>> VBIOS to describe this kind of information to us, hence we haven't seen this >>> before. For CPUs there are plenty of examples though of such params defined >>> in DT: in arch/arm/boot/dts/ : imx6qdl.dtsi documents the min and max volt >>> for regulators, while the CPUs have a little freq<->volt mapping in >>> imx6q.dtsi. GPUs are new in a sense that NVIDIA is the first to actively >>> support upstream development (thanks!) >> Thanks for raising this point. I agree with your interpretation that >> DT is comparable to the VBIOS in desktop GPUs. The question then >> becomes whether this data can vary between different GK20A-using >> boards (and in this case this should probably be part of DT) or not >> (in which case I would advocate having this static information in the >> driver itself). Since I don't expect different GK20A-using chips to >> require different voltage for given frequencies, my gut feeling for >> the moment is that having this information in the driver is fine. I >> have added a few other NVIDIA people to gather thoughts. > > The voltage<->frequency relationship is per chip, not per board. We read > the chip id at runtime, and programmatically determine the DVFS steps > based on that. CVB table contains the parameters for the algorithm. > > I think the table belongs in the driver. The table is not per board, and > the values in CVB table do not describe hardware, but parameters to an > algorithm.
In that case I also think it would make more sense (and make things easier) to have these tables in the driver. Roy, do you have any objection? _______________________________________________ Nouveau mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/nouveau
