Hi Uli,
(Replying to an old series, now we have received more background
information)
On Fri, Jan 18, 2019 at 11:48 AM Ulrich Hecht <uli+renesas@xxxxxxxx> wrote:
> This series adds CPU idle support for H3 and M3-W. It's a straight up-port
> from the BSP. This revision removes the superfluous status properties from
> the idle states and fixes Khiem's e-mail address.
> Dien Pham (2):
> arm64: dts: r8a7795: Add cpuidle support for CA53 cores
> arm64: dts: r8a7796: Add cpuidle support for CA53 cores
>
> Khiem Nguyen (2):
> arm64: dts: r8a7795: Add cpuidle support for CA57 cores
> arm64: dts: r8a7796: Add cpuidle support for CA57 cores
Thanks for the update!
I took the liberty to create a topic branch[1] for the first 4 patches,
and include it in yesterday's renesas-drivers-2019-08-27-v5.3-rc6.
> I don't think we have any information on whether all M3ULCB boards have an
> ES1.0 SoC yet, do we?
> Takeshi Kihara (1):
> arm64: dts: r8a7796-m3ulcb: Disable cpuidle support for CA53 cores
This is just one possible mitigation for a system controller issue, to
prevent conflicts between powering off CPU cores or the 3D Graphics
Engine, and changing the state of another power domain through SYSC,
which could lead to CPG state machine lock-ups.
Other mitigations are to make use of the new System Controller External
Request Mask Register[2], present in newer SoCs and SoC revisions, or to
keep some power areas always powered.
However, we believe this issue cannot happen in the upstream kernel, as
upstream has no support for graphics acceleration yet.
Hence I think this series (modulo the last patch) is ready to be queued
in renesas-devel for v5.5.
Thanks for your comments!
[1] git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers.git#topic/rcar3-cpuidle-v2
[2] "[PATCH v2 0/7] soc: renesas: rcar-gen3-sysc: Fix power request conflicts"
(https://lore.kernel.org/linux-renesas-soc/20190828113618.6672-1-geert+renesas@xxxxxxxxx/)
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
