linux-kernel - Re: [PATCH] thermal/drivers/sun8i: Don't fail probe due to zone registration failure

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Message-ID: <3240466.aeNJFYEL58@jernej-laptop>
Date:   Wed, 19 Jul 2023 22:24:55 +0200
From:   Jernej Škrabec <jernej.skrabec@...il.com>
To:     Vasily Khoruzhick <anarsoul@...il.com>,
        Yangtao Li <tiny.windzz@...il.com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Amit Kucheria <amitk@...nel.org>,
        Zhang Rui <rui.zhang@...el.com>, Chen-Yu Tsai <wens@...e.org>,
        Samuel Holland <samuel@...lland.org>,
        Mark Brown <broonie@...nel.org>
Cc:     Hugh Dickins <hughd@...gle.com>, linux-pm@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-sunxi@...ts.linux.dev,
        linux-kernel@...r.kernel.org, Mark Brown <broonie@...nel.org>
Subject: Re: [PATCH] thermal/drivers/sun8i: Don't fail probe due to zone registration
 failure

Dne torek, 18. julij 2023 ob 17:04:22 CEST je Mark Brown napisal(a):
> Currently the sun8i thermal driver will fail to probe if any of the
> thermal zones it is registering fails to register with the thermal core.
> Since we currently do not define any trip points for the GPU thermal
> zones on at least A64 or H5 this means that we have no thermal support
> on these platforms:
> 
> [    1.698703] thermal_sys: Failed to find 'trips' node
> [    1.698707] thermal_sys: Failed to find trip points for thermal-sensor
> id=1
> 
> even though the main CPU thermal zone on both SoCs is fully configured.
> This does not seem ideal, while we may not be able to use all the zones
> it seems better to have those zones which are usable be operational.
> Instead just carry on registering zones if we get any non-deferral
> error, allowing use of those zones which are usable.
> 
> This means that we also need to update the interrupt handler to not
> attempt to notify the core for events on zones which we have not
> registered, I didn't see an ability to mask individual interrupts and
> I would expect that interrupts would still be indicated in the ISR even
> if they were masked.
> 
> Signed-off-by: Mark Brown <broonie@...nel.org>

Acked-by: Jernej Skrabec <jernej.skrabec@...il.com>

Best regards,
Jernej

> ---
> I noticed this while trying to debug an issue with memory corruption on
> boot which since the merge window has prevented Pine64 Plus (an A64)
> from booting at all:
> 
>   
> https://storage.kernelci.org/mainline/master/v6.5-rc2/arm64/defconfig/gcc-1
> 0/lab-baylibre/baseline-sun50i-a64-pine64-plus.txt
> 
> (which I bisected to a random memory management change that clearly
> wasn't at fault) and has been causing less consistent but still very
> severe boot issues on Libretech Tritium (a H3).  The corruption appears
> to happen when unbinding a the one thermal zone that does register, I've
> not figured out exactly where.
> 
> The memory corruption issue obviously needs to be dealt with properly
> (I'm still digging into it) but this does allow both platforms to boot
> reliably and seems like a sensible thing to do independently, ideally we
> could get this in as a fix.
> ---
>  drivers/thermal/sun8i_thermal.c | 16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/thermal/sun8i_thermal.c
> b/drivers/thermal/sun8i_thermal.c index 195f3c5d0b38..b69134538867 100644
> --- a/drivers/thermal/sun8i_thermal.c
> +++ b/drivers/thermal/sun8i_thermal.c
> @@ -190,6 +190,9 @@ static irqreturn_t sun8i_irq_thread(int irq, void *data)
> int i;
> 
>  	for_each_set_bit(i, &irq_bitmap, tmdev->chip->sensor_num) {
> +		/* We allow some zones to not register. */
> +		if (IS_ERR(tmdev->sensor[i].tzd))
> +			continue;
>  		thermal_zone_device_update(tmdev->sensor[i].tzd,
>  					   
THERMAL_EVENT_UNSPECIFIED);
>  	}
> @@ -465,8 +468,17 @@ static int sun8i_ths_register(struct ths_device *tmdev)
> i,
>  						      
&tmdev->sensor[i],
>  						      
&ths_ops);
> -		if (IS_ERR(tmdev->sensor[i].tzd))
> -			return PTR_ERR(tmdev->sensor[i].tzd);
> +
> +		/*
> +		 * If an individual zone fails to register for reasons
> +		 * other than probe deferral (eg, a bad DT) then carry
> +		 * on, other zones might register successfully.
> +		 */
> +		if (IS_ERR(tmdev->sensor[i].tzd)) {
> +			if (PTR_ERR(tmdev->sensor[i].tzd) == -
EPROBE_DEFER)
> +				return PTR_ERR(tmdev-
>sensor[i].tzd);
> +			continue;
> +		}
> 
>  		devm_thermal_add_hwmon_sysfs(tmdev->dev, tmdev-
>sensor[i].tzd);
>  	}
> 
> ---
> base-commit: fdf0eaf11452d72945af31804e2a1048ee1b574c
> change-id: 20230718-thermal-sun8i-registration-df3a136ccafa
> 
> Best regards,