linux-kernel - Re: [PATCH] net: stmmac: dwmac-rk: fix unbalanced pm_runtime

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Date:   Mon, 30 Aug 2021 16:10:46 +0200
From:   Michael Riesch <michael.riesch@...fvision.net>
To:     Punit Agrawal <punitagrawal@...il.com>
Cc:     wens@...nel.org, netdev <netdev@...r.kernel.org>,
        "moderated list:ARM/STM32 ARCHITECTURE" 
        <linux-stm32@...md-mailman.stormreply.com>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@...ts.infradead.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Giuseppe Cavallaro <peppe.cavallaro@...com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        Jose Abreu <joabreu@...opsys.com>,
        "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>, sashal@...nel.org
Subject: Re: [PATCH] net: stmmac: dwmac-rk: fix unbalanced pm_runtime_enable
 warnings

Hi Punit,

On 8/30/21 3:49 PM, Punit Agrawal wrote:
> Hi Michael,
> 
> Michael Riesch <michael.riesch@...fvision.net> writes:
> 
>> Hi ChenYu,
>>
>> On 8/29/21 7:48 PM, Chen-Yu Tsai wrote:
>>> Hi,
>>>
>>> On Mon, Aug 23, 2021 at 10:39 PM Michael Riesch
>>> <michael.riesch@...fvision.net> wrote:
>>>>
>>>> This reverts commit 2c896fb02e7f65299646f295a007bda043e0f382
>>>> "net: stmmac: dwmac-rk: add pd_gmac support for rk3399" and fixes
>>>> unbalanced pm_runtime_enable warnings.
>>>>
>>>> In the commit to be reverted, support for power management was
>>>> introduced to the Rockchip glue code. Later, power management support
>>>> was introduced to the stmmac core code, resulting in multiple
>>>> invocations of pm_runtime_{enable,disable,get_sync,put_sync}.
>>>>
>>>> The multiple invocations happen in rk_gmac_powerup and
>>>> stmmac_{dvr_probe, resume} as well as in rk_gmac_powerdown and
>>>> stmmac_{dvr_remove, suspend}, respectively, which are always called
>>>> in conjunction.
>>>>
>>>> Signed-off-by: Michael Riesch <michael.riesch@...fvision.net>
>>>
>>> I just found that Ethernet stopped working on my RK3399 devices,
>>> and I bisected it down to this patch.
>>
>> Oh dear. First patch in a kernel release for a while and I already break
>> things.
> 
> I am seeing the same failure symptoms reported by ChenYu on my RockPro64
> with v5.14. Reverting the revert i.e., 2d26f6e39afb ("net: stmmac:
> dwmac-rk: fix unbalanced pm_runtime_enable warnings") brings back the
> network.
> 
>> Cc: Sasha as this patch has just been applied to 5.13-stable.
>>
>>> The symptom I see is no DHCP responses, either because the request
>>> isn't getting sent over the wire, or the response isn't getting
>>> received. The PHY seems to be working correctly.
>>
>> Unfortunately I don't have any RK3399 hardware. Is this a custom
>> board/special hardware or something that is readily available in the
>> shops? Maybe this is a good reason to buy a RK3399 based single-board
>> computer :-)
> 
> Not sure about the other RK3399 boards but RockPro64 is easily
> available.

I was thinking to get one of those anyway ;-)

>> I am working on the RK3568 EVB1 and have not encountered faulty
>> behavior. DHCP works fine and I can boot via NFS. Therefore, not sure
>> whether I can be much of help in this matter, but in case you want to
>> discuss this further please do not hesitate to contact me off-list.
> 
> I tried to look for the differences between RK3568 and RK3399 but the
> upstream device tree doesn't seem to carry a gmac node in the device
> tree for EK3568 EVB1. Do you have a pointer for the dts you're using?

The gmac nodes have been added recently and should enter 5.15-rc1. Until
then, you can check out the dts from linux-rockchip/for-next [0].

> Also, other than the warning "Unbalanced pm_runtime_enable!" do you
> notice any other ill-effects without your patch?

No, not as such.

Best regards,
Michael

> If this affects all RK3399 boards as ChenYu suggests quite a few users
> are going to miss the network once they upgrade.>
> Punit
> 
> [...]
> 

[0]
https://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip.git/log/?h=for-next