* Re: [PATCH] backlight: pwm_bl: re-add driver internal enabled tracking
2018-11-09 9:48 [PATCH] backlight: pwm_bl: re-add driver internal enabled tracking Heiko Stuebner
@ 2018-11-09 10:15 ` Enric Balletbo i Serra
2018-11-14 9:11 ` Uwe Kleine-König
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Enric Balletbo i Serra @ 2018-11-09 10:15 UTC (permalink / raw)
To: Heiko Stuebner, lee.jones, daniel.thompson, jingoohan1
Cc: linux-pwm, thierry.reding, dri-devel
Hi Heiko,
Many thanks to catch and dig into this, I did more tests but I was not able to
reproduce the issue with my nfs environment. Anyway the patch looks good to me
and fixes the issue for you, so
On 9/11/18 10:48, Heiko Stuebner wrote:
> Commit e6bcca0890b9 ("backlight: pwm_bl: Switch to using "atomic" PWM API")
> removed the driver internal enabled tracking in favor of simply checking
> the pwm state.
>
> This can lead to issues as all of gpio-, regulator- and pwm-state are used
> to determine the initial state and the bootloader or kernel can leave them
> in an inconsistent state at boot.
>
> In my case on rk3399-kevin, the pwm backlight is build as module and the
> kernel disables the supply regulator as unused while keeping the pwm running
> thus pwm_bl calling pwm_backlight_power_off() during probe and creating an
> unmatched regulator-disable call, as it never got enabled from the pwm-bl
> before.
>
> To prevent these consistency issues, reintroduce the driver-internal
> tracking of the enabled state.
>
> Fixes: e6bcca0890b9 ("backlight: pwm_bl: Switch to using "atomic" PWM API")
> Signed-off-by: Heiko Stuebner <heiko@sntech.de>
> ---
> drivers/video/backlight/pwm_bl.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
> index 678b27063198..bcd08b41765d 100644
> --- a/drivers/video/backlight/pwm_bl.c
> +++ b/drivers/video/backlight/pwm_bl.c
> @@ -30,6 +30,7 @@ struct pwm_bl_data {
> struct device *dev;
> unsigned int lth_brightness;
> unsigned int *levels;
> + bool enabled;
> struct regulator *power_supply;
> struct gpio_desc *enable_gpio;
> unsigned int scale;
> @@ -50,7 +51,7 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb)
> int err;
>
> pwm_get_state(pb->pwm, &state);
> - if (state.enabled)
> + if (pb->enabled)
> return;
>
> err = regulator_enable(pb->power_supply);
> @@ -65,6 +66,8 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb)
>
> if (pb->enable_gpio)
> gpiod_set_value_cansleep(pb->enable_gpio, 1);
> +
> + pb->enabled = true;
> }
>
> static void pwm_backlight_power_off(struct pwm_bl_data *pb)
> @@ -72,7 +75,7 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb)
> struct pwm_state state;
>
> pwm_get_state(pb->pwm, &state);
> - if (!state.enabled)
> + if (!pb->enabled)
> return;
>
> if (pb->enable_gpio)
> @@ -86,6 +89,7 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb)
> pwm_apply_state(pb->pwm, &state);
>
> regulator_disable(pb->power_supply);
> + pb->enabled = false;
> }
>
> static int compute_duty_cycle(struct pwm_bl_data *pb, int brightness)
> @@ -483,6 +487,7 @@ static int pwm_backlight_probe(struct platform_device *pdev)
> pb->check_fb = data->check_fb;
> pb->exit = data->exit;
> pb->dev = &pdev->dev;
> + pb->enabled = false;
> pb->post_pwm_on_delay = data->post_pwm_on_delay;
> pb->pwm_off_delay = data->pwm_off_delay;
>
>
Reviewed-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
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^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] backlight: pwm_bl: re-add driver internal enabled tracking
2018-11-09 9:48 [PATCH] backlight: pwm_bl: re-add driver internal enabled tracking Heiko Stuebner
2018-11-09 10:15 ` Enric Balletbo i Serra
@ 2018-11-14 9:11 ` Uwe Kleine-König
2018-11-14 12:35 ` Thierry Reding
2018-11-16 10:22 ` Daniel Thompson
3 siblings, 0 replies; 5+ messages in thread
From: Uwe Kleine-König @ 2018-11-14 9:11 UTC (permalink / raw)
To: Heiko Stuebner
Cc: linux-pwm, daniel.thompson, jingoohan1, dri-devel, thierry.reding,
enric.balletbo, lee.jones
Hello Heiko,
On Fri, Nov 09, 2018 at 10:48:57AM +0100, Heiko Stuebner wrote:
> Commit e6bcca0890b9 ("backlight: pwm_bl: Switch to using "atomic" PWM API")
> removed the driver internal enabled tracking in favor of simply checking
> the pwm state.
>
> This can lead to issues as all of gpio-, regulator- and pwm-state are used
> to determine the initial state and the bootloader or kernel can leave them
> in an inconsistent state at boot.
>
> In my case on rk3399-kevin, the pwm backlight is build as module and the
> kernel disables the supply regulator as unused while keeping the pwm running
> thus pwm_bl calling pwm_backlight_power_off() during probe and creating an
> unmatched regulator-disable call, as it never got enabled from the pwm-bl
> before.
>
> To prevent these consistency issues, reintroduce the driver-internal
> tracking of the enabled state.
>
> Fixes: e6bcca0890b9 ("backlight: pwm_bl: Switch to using "atomic" PWM API")
> Signed-off-by: Heiko Stuebner <heiko@sntech.de>
This looks right,
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] backlight: pwm_bl: re-add driver internal enabled tracking
2018-11-09 9:48 [PATCH] backlight: pwm_bl: re-add driver internal enabled tracking Heiko Stuebner
2018-11-09 10:15 ` Enric Balletbo i Serra
2018-11-14 9:11 ` Uwe Kleine-König
@ 2018-11-14 12:35 ` Thierry Reding
2018-11-16 10:22 ` Daniel Thompson
3 siblings, 0 replies; 5+ messages in thread
From: Thierry Reding @ 2018-11-14 12:35 UTC (permalink / raw)
To: Heiko Stuebner
Cc: linux-pwm, daniel.thompson, jingoohan1, dri-devel, enric.balletbo,
lee.jones
[-- Attachment #1.1: Type: text/plain, Size: 1170 bytes --]
On Fri, Nov 09, 2018 at 10:48:57AM +0100, Heiko Stuebner wrote:
> Commit e6bcca0890b9 ("backlight: pwm_bl: Switch to using "atomic" PWM API")
> removed the driver internal enabled tracking in favor of simply checking
> the pwm state.
>
> This can lead to issues as all of gpio-, regulator- and pwm-state are used
> to determine the initial state and the bootloader or kernel can leave them
> in an inconsistent state at boot.
>
> In my case on rk3399-kevin, the pwm backlight is build as module and the
> kernel disables the supply regulator as unused while keeping the pwm running
> thus pwm_bl calling pwm_backlight_power_off() during probe and creating an
> unmatched regulator-disable call, as it never got enabled from the pwm-bl
> before.
>
> To prevent these consistency issues, reintroduce the driver-internal
> tracking of the enabled state.
>
> Fixes: e6bcca0890b9 ("backlight: pwm_bl: Switch to using "atomic" PWM API")
> Signed-off-by: Heiko Stuebner <heiko@sntech.de>
> ---
> drivers/video/backlight/pwm_bl.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
Acked-by: Thierry Reding <thierry.reding@gmail.com>
[-- Attachment #1.2: signature.asc --]
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[-- Attachment #2: Type: text/plain, Size: 160 bytes --]
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^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] backlight: pwm_bl: re-add driver internal enabled tracking
2018-11-09 9:48 [PATCH] backlight: pwm_bl: re-add driver internal enabled tracking Heiko Stuebner
` (2 preceding siblings ...)
2018-11-14 12:35 ` Thierry Reding
@ 2018-11-16 10:22 ` Daniel Thompson
3 siblings, 0 replies; 5+ messages in thread
From: Daniel Thompson @ 2018-11-16 10:22 UTC (permalink / raw)
To: Heiko Stuebner
Cc: linux-pwm, jingoohan1, dri-devel, thierry.reding, enric.balletbo,
lee.jones
On Fri, Nov 09, 2018 at 10:48:57AM +0100, Heiko Stuebner wrote:
> Commit e6bcca0890b9 ("backlight: pwm_bl: Switch to using "atomic" PWM API")
> removed the driver internal enabled tracking in favor of simply checking
> the pwm state.
>
> This can lead to issues as all of gpio-, regulator- and pwm-state are used
> to determine the initial state and the bootloader or kernel can leave them
> in an inconsistent state at boot.
>
> In my case on rk3399-kevin, the pwm backlight is build as module and the
> kernel disables the supply regulator as unused while keeping the pwm running
> thus pwm_bl calling pwm_backlight_power_off() during probe and creating an
> unmatched regulator-disable call, as it never got enabled from the pwm-bl
> before.
>
> To prevent these consistency issues, reintroduce the driver-internal
> tracking of the enabled state.
>
> Fixes: e6bcca0890b9 ("backlight: pwm_bl: Switch to using "atomic" PWM API")
> Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
> ---
> drivers/video/backlight/pwm_bl.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
> index 678b27063198..bcd08b41765d 100644
> --- a/drivers/video/backlight/pwm_bl.c
> +++ b/drivers/video/backlight/pwm_bl.c
> @@ -30,6 +30,7 @@ struct pwm_bl_data {
> struct device *dev;
> unsigned int lth_brightness;
> unsigned int *levels;
> + bool enabled;
> struct regulator *power_supply;
> struct gpio_desc *enable_gpio;
> unsigned int scale;
> @@ -50,7 +51,7 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb)
> int err;
>
> pwm_get_state(pb->pwm, &state);
> - if (state.enabled)
> + if (pb->enabled)
> return;
>
> err = regulator_enable(pb->power_supply);
> @@ -65,6 +66,8 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb)
>
> if (pb->enable_gpio)
> gpiod_set_value_cansleep(pb->enable_gpio, 1);
> +
> + pb->enabled = true;
> }
>
> static void pwm_backlight_power_off(struct pwm_bl_data *pb)
> @@ -72,7 +75,7 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb)
> struct pwm_state state;
>
> pwm_get_state(pb->pwm, &state);
> - if (!state.enabled)
> + if (!pb->enabled)
> return;
>
> if (pb->enable_gpio)
> @@ -86,6 +89,7 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb)
> pwm_apply_state(pb->pwm, &state);
>
> regulator_disable(pb->power_supply);
> + pb->enabled = false;
> }
>
> static int compute_duty_cycle(struct pwm_bl_data *pb, int brightness)
> @@ -483,6 +487,7 @@ static int pwm_backlight_probe(struct platform_device *pdev)
> pb->check_fb = data->check_fb;
> pb->exit = data->exit;
> pb->dev = &pdev->dev;
> + pb->enabled = false;
> pb->post_pwm_on_delay = data->post_pwm_on_delay;
> pb->pwm_off_delay = data->pwm_off_delay;
>
> --
> 2.18.0
>
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^ permalink raw reply [flat|nested] 5+ messages in thread