Hello Daniel,
On 2024-08-19 17:42, Daniel Lezcano wrote:
On 12/08/2024 04:46, Dragan Simic wrote:
On 2024-08-12 04:40, Icenowy Zheng wrote:
在 2024-08-12星期一的 04:00 +0200，Dragan Simic写道：
Add thermal trips for the two GPU thermal sensors found in the
Allwinner A64.
There's only one GPU OPP defined since the commit 1428f0c19f9c
("arm64: dts:
allwinner: a64: Run GPU at 432 MHz"), so defining only the critical
thermal
trips makes sense for the A64's two GPU thermal zones.
Having these critical thermal trips defined ensures that no hot
spots
develop
inside the SoC die that exceed the maximum junction temperature.
That might
have been possible before, although quite unlikely, because the CPU
and GPU
portions of the SoC are packed closely inside the SoC, so the
overheating GPU
would inevitably result in the heat soaking into the CPU portion of
the SoC,
causing the CPU thermal sensor to return high readings and trigger
the CPU
critical thermal trips. However, it's better not to rely on the
heat
soak
and have the critical GPU thermal trips properly defined instead.
While there, remove a few spotted comments that are rather
redundant,
because
it's pretty much obvious what units are used in those places.
This should be another individual patch, I think.
Perhaps, which I already thought about, but it might also be best
to simply drop the removal of those redundant comments entirely.
Let's also see what will other people say.
Signed-off-by: Dragan Simic <dsimic@xxxxxxxxxxx>
---
arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi | 22
++++++++++++++---
-- 1 file changed, 16 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
b/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
index e868ca5ae753..bc5d3a2e6c98 100644
--- a/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
+++ b/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
@@ -212,7 +212,6 @@ timer {
thermal-zones {
cpu_thermal: cpu0-thermal {
- /* milliseconds */
The unit of a 0 isn't not so obvious I think, so I suggest to keep
this.
Quite frankly, I think it should be obvious to anyone tackling
the thermal zones and trips.
You can remove also polling-delay-passive and polling-passive when
they are equal to zero. If they are absent they will be set to zero by
default.
Good point, thanks! Though, I'd rather leave those "... = <0>;"
removals for a small follow-up series, because those changes touch
more actual code than just the comments, so it's better to keep them
as separate changes for easier bisection later, if it's ever needed.
Hopefully never. :)
I just made a note for myself to create and submit those follow-up
cleanup patches later, for all affected Allwinner and Rockchip SoC
dtsi files.
That said, I take the opportunity to spot some inconsistency in this
DT not related to this change.
1. There is a passive trip point and one cooling device mapped to it.
With a polling-delay-passive=0, the mitigation will fail
Huh, how is the CPU throttling working then? Thanks for pointing it
out, I'll address this issue in the follow-up patches.
2. There is a second mapping for the hot trip point. That does not
make sense, it is not possible because there is no mitigation for
'hot' and 'critical' trip points.
Yup, I see no special handling of tz->ops.hot, so having the hot trip
point makes no sense. Thanks again for pointing it out, I'll address
this issue in the follow-up patches as well.
I'll send the v2 soon, as a small patch series, and I'll send a few
follow-up patches later.
