<jernej>
apritzel: what is biggest improvement in GICv3? I mean, what incentive would company have to integrate newer GIC, if old will do?
<apritzel>
jernej: two killer features: support for more than 8 cores (this is a hard architectural limit in GICv2), plus using system registers for the GIC CPU interface instead of MMIO
<apritzel>
per-core banked MMIO has higher latency and is harder to implement in modern SoCs
<jernej>
so 1) not relevant for AW, at least with existing SoCs
<apritzel>
exactly
<jernej>
and second?
<apritzel>
second is the system register interface I mentioned, which is architectural and integrated into the core
<jernej>
so lower latency as you mentioned before?
<jernej>
is this latency really so much relevant for non RT work?
<apritzel>
no
<apritzel>
also: newer Arm Ltd. cores (starting with the ARMv8.2 parts, so A55/A75 and beyond) don't support the GICv2 CPU side anymore, at least on the face of it
<apritzel>
that is probably more of an issue, but as Amlogic proved, it can be hack^Wworked around
<jernej>
ok, this sounds more important for me :)
<jernej>
ah, many things can be achieved, given enough resources and motivation
<apritzel>
so that's what I meant on the weekend: there is really no *pressing* reason for AW to use a GICv3, and they strike me as the kind of vendor pulling of this GIC-400 hack that Amlogic did
<gamiee>
well, Allwinner is recently quite silent, almost no new (ARM) SoCs out (only D1 and D1s, but that's... at least for me not that interesting)
<apritzel>
MSIs are handled better with a GICv3 (admittedly at the cost of quite some complexity with the ITS), but for that PCIe level that AW uses it doesn't seem relevant
<apritzel>
gamiee: I think they released quite some SoCs, but is mostly specialised (read: not-interesting) SoCs, many with Cortex-A7 still
<gamiee>
apritzel: which ones?
<apritzel>
gamiee: various in the R and T series
<gamiee>
will take look, thx
<apritzel>
gamiee: some are not really well advertised, but there is evidence in some BSP code. It smells like very specific chips for one use case (for instance dashboard cameras or "smart" speakers)
evgeny_boger has joined #linux-sunxi
evgeny_boger has quit [Ping timeout: 480 seconds]
evgeny_boger has joined #linux-sunxi
vagrantc has joined #linux-sunxi
hlauer has joined #linux-sunxi
evgeny_boger has quit [Ping timeout: 480 seconds]
apritzel has quit [Ping timeout: 480 seconds]
vagrantc has quit [Quit: leaving]
JohnDoe_71Rus has quit []
apritzel has joined #linux-sunxi
apritzel has quit [Ping timeout: 480 seconds]
<gamiee>
apritzel: yes, V-series chips are interesting, but I don't understand why Allwinner hiding their V831/V833 that much (also why they hides the fact it haves NNA)
Luke-Jr has quit [Ping timeout: 480 seconds]
Luke-Jr has joined #linux-sunxi
vagrantc has joined #linux-sunxi
suniel has quit [Remote host closed the connection]