linux-kernel - Re: [PATCH 5/9] ARM: dts: exynos: move exynos-bus nodes out of soc in Exynos4412

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Message-ID: <f66f01d0-372a-1c22-3005-9c5bc65d8fa5@fivetechno.de>
Date:   Fri, 3 Feb 2023 12:53:21 +0100
From:   Markus Reichl <m.reichl@...etechno.de>
To:     Marek Szyprowski <m.szyprowski@...sung.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Alim Akhtar <alim.akhtar@...sung.com>,
        Kukjin Kim <kgene@...nel.org>, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     replicant@...osl.org, phone-devel@...r.kernel.org,
        ~postmarketos/upstreaming@...ts.sr.ht,
        Martin Jücker <martin.juecker@...il.com>,
        Henrik Grimler <henrik@...mler.se>,
        Chanwoo Choi <cw00.choi@...sung.com>
Subject: Re: [PATCH 5/9] ARM: dts: exynos: move exynos-bus nodes out of soc in
 Exynos4412

Hi Marek,

Am 03.02.23 um 12:45 schrieb Marek Szyprowski:
> Hi Krzysztof,
> 
> On 29.01.2023 11:42, Krzysztof Kozlowski wrote:
>> On 25/01/2023 10:45, Krzysztof Kozlowski wrote:
>>> The soc node is supposed to have only device nodes with MMIO addresses,
>>> as reported by dtc W=1:
>>>
>>>    exynos4412.dtsi:407.20-413.5:
>>>      Warning (simple_bus_reg): /soc/bus-acp: missing or empty reg/ranges property
>>>
>>> and dtbs_check:
>>>
>>>    exynos4412-i9300.dtb: soc: bus-acp:
>>>      {'compatible': ['samsung,exynos-bus'], 'clocks': [[7, 456]], 'clock-names': ['bus'], 'operating-points-v2': [[132]], 'status': ['okay'], 'devfreq': [[117]]} should not be valid under {'type': 'object'}
>>>
>>> Move the bus nodes and their OPP tables out of SoC to fix this.
>>> Re-order them alphabetically while moving and put some of the OPP tables
>>> in device nodes (if they are not shared).
>>>
>> Applied.
> 
> I don't have a good news. It looks that this change is responsible for
> breaking boards that were rock-stable so far, like Odroid U3. I didn't
> manage to analyze what exactly causes the issue, but it looks that the
> exynos-bus devfreq driver somehow depends on the order of the nodes:
> 
> (before)
> 
> # dmesg | grep exynos-bus
> [    6.415266] exynos-bus: new bus device registered: soc:bus-dmc
> (100000 KHz ~ 400000 KHz)
> [    6.422717] exynos-bus: new bus device registered: soc:bus-acp
> (100000 KHz ~ 267000 KHz)
> [    6.454323] exynos-bus: new bus device registered: soc:bus-c2c
> (100000 KHz ~ 400000 KHz)
> [    6.489944] exynos-bus: new bus device registered: soc:bus-leftbus
> (100000 KHz ~ 200000 KHz)
> [    6.493990] exynos-bus: new bus device registered: soc:bus-rightbus
> (100000 KHz ~ 200000 KHz)
> [    6.494612] exynos-bus: new bus device registered: soc:bus-display
> (160000 KHz ~ 200000 KHz)
> [    6.494932] exynos-bus: new bus device registered: soc:bus-fsys
> (100000 KHz ~ 134000 KHz)
> [    6.495246] exynos-bus: new bus device registered: soc:bus-peri (
> 50000 KHz ~ 100000 KHz)
> [    6.495577] exynos-bus: new bus device registered: soc:bus-mfc
> (100000 KHz ~ 200000 KHz)
> 
> (after)
> 
> # dmesg | grep exynos-bus
> 
> [    6.082032] exynos-bus: new bus device registered: bus-dmc (100000
> KHz ~ 400000 KHz)
> [    6.122726] exynos-bus: new bus device registered: bus-leftbus
> (100000 KHz ~ 200000 KHz)
> [    6.146705] exynos-bus: new bus device registered: bus-mfc (100000
> KHz ~ 200000 KHz)
> [    6.181632] exynos-bus: new bus device registered: bus-peri ( 50000
> KHz ~ 100000 KHz)
> [    6.204770] exynos-bus: new bus device registered: bus-rightbus
> (100000 KHz ~ 200000 KHz)
> [    6.211087] exynos-bus: new bus device registered: bus-acp (100000
> KHz ~ 267000 KHz)
> [    6.216936] exynos-bus: new bus device registered: bus-c2c (100000
> KHz ~ 400000 KHz)
> [    6.225748] exynos-bus: new bus device registered: bus-display
> (160000 KHz ~ 200000 KHz)
> [    6.242978] exynos-bus: new bus device registered: bus-fsys (100000
> KHz ~ 134000 KHz)
> 
> This is definitely a driver bug, but so far it worked fine, so this is a
> regression that need to be addressed somehow...
> 
> Best regards

the exynos-bus devfreq driver is not so solid on exynos-4412-boards.
On my 24/7 odroid-x2 I need
echo performance > /sys/class/devfreq/soc:bus-leftbus/governor
to avoid random hangs.

Gruß,
-- 
Markus Reichl