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SubjectRe: [PATCH] thermal: exynos: Reduce severity of too early temperature read
Date
On Sunday, May 13, 2018 07:54:02 PM Krzysztof Kozlowski wrote:
> Thermal core tries to read temperature during sensor registering in
> thermal_zone_of_sensor_register(). In that time Exynos TMU driver and
> hardware are not yet initialized. Commit 0eb875d88aaa ("thermal:
> exynos: Reading temperature makes sense only when TMU is turned on")
> added a boolean flag to prevent reading bogus temperature in such
> case but it exposed warning message during boot:
> [ 3.864913] thermal thermal_zone0: failed to read out thermal zone (-22)
>
> Return EAGAIN in such case to skip omitting such message because it
> might mislead user.

Hi Krzysztof,

I've fixed this in generic way a month ago:

https://lkml.org/lkml/2018/4/10/376

(there has been not much feedback on it yet)

However since my patchset is not v4.17 material:

> Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Eduardo, please queue it for v4.17 if possible, thanks.

> ---
> drivers/thermal/samsung/exynos_tmu.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/thermal/samsung/exynos_tmu.c b/drivers/thermal/samsung/exynos_tmu.c
> index 3b20309789e3..c24969d740d1 100644
> --- a/drivers/thermal/samsung/exynos_tmu.c
> +++ b/drivers/thermal/samsung/exynos_tmu.c
> @@ -666,8 +666,14 @@ static int exynos_get_temp(void *p, int *temp)
> struct exynos_tmu_data *data = p;
> int value, ret = 0;
>
> - if (!data || !data->tmu_read || !data->enabled)
> + if (!data || !data->tmu_read)
> return -EINVAL;
> + else if (!data->enabled)
> + /*
> + * Called too early, probably
> + * from thermal_zone_of_sensor_register().
> + */
> + return -EAGAIN;
>
> mutex_lock(&data->lock);
> clk_enable(data->clk);

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

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