backlight: pwm_bl: Fix condition to set enable gpio as output

Submitted by Paul Kocialkowski on April 16, 2017, 10:35 a.m.

Details

Message ID 20170416103546.3021-1-contact@paulk.fr
State New
Headers show

Commit Message

Paul Kocialkowski April 16, 2017, 10:35 a.m.
The move to a dedicated pwm_backlight_initial_power_state function in
commit 7613c922315e308a6486d802abed2eb74443dffd modified the condition
to set the enable gpio as output. This breaks specific use cases using
that GPIO, such as tegra124-based nyan Chromebooks where backlight
stopped working.

This puts the condition back to the way it was before the move.

Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
---
 drivers/video/backlight/pwm_bl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Geert Uytterhoeven April 16, 2017, 8:55 p.m.
Hi Paul,

On Sun, Apr 16, 2017 at 12:35 PM, Paul Kocialkowski <contact@paulk.fr> wrote:
> The move to a dedicated pwm_backlight_initial_power_state function in
> commit 7613c922315e308a6486d802abed2eb74443dffd modified the condition
> to set the enable gpio as output. This breaks specific use cases using
> that GPIO, such as tegra124-based nyan Chromebooks where backlight
> stopped working.
>
> This puts the condition back to the way it was before the move.
>
> Signed-off-by: Paul Kocialkowski <contact@paulk.fr>

Does "[PATCH v2] backlight: pwm_bl: Fix GPIO out for unimplemented
.get_direction()"
(https://lkml.org/lkml/2017/4/4/225) fix your issue?

Thanks!

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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Paul Kocialkowski April 17, 2017, 3:38 p.m.
Hi,

Le dimanche 16 avril 2017 à 22:55 +0200, Geert Uytterhoeven a écrit :
> On Sun, Apr 16, 2017 at 12:35 PM, Paul Kocialkowski <contact@paulk.fr> wrote:
> > The move to a dedicated pwm_backlight_initial_power_state function in
> > commit 7613c922315e308a6486d802abed2eb74443dffd modified the condition
> > to set the enable gpio as output. This breaks specific use cases using
> > that GPIO, such as tegra124-based nyan Chromebooks where backlight
> > stopped working.
> > 
> > This puts the condition back to the way it was before the move.
> > 
> > Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
> 
> Does "[PATCH v2] backlight: pwm_bl: Fix GPIO out for unimplemented
> .get_direction()"
> (https://lkml.org/lkml/2017/4/4/225) fix your issue?

This definitely solves the issue!

Since this fixes broken backlight (that, in turn, makes systems unusable),
perhaps this should be included in the next rc cycle?

Cheers!
Geert Uytterhoeven April 17, 2017, 7:36 p.m.
Hi Paul,

On Mon, Apr 17, 2017 at 5:38 PM, Paul Kocialkowski <contact@paulk.fr> wrote:
> Le dimanche 16 avril 2017 à 22:55 +0200, Geert Uytterhoeven a écrit :
>> On Sun, Apr 16, 2017 at 12:35 PM, Paul Kocialkowski <contact@paulk.fr> wrote:
>> > The move to a dedicated pwm_backlight_initial_power_state function in
>> > commit 7613c922315e308a6486d802abed2eb74443dffd modified the condition
>> > to set the enable gpio as output. This breaks specific use cases using
>> > that GPIO, such as tegra124-based nyan Chromebooks where backlight
>> > stopped working.
>> >
>> > This puts the condition back to the way it was before the move.
>> >
>> > Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
>>
>> Does "[PATCH v2] backlight: pwm_bl: Fix GPIO out for unimplemented
>> .get_direction()"
>> (https://lkml.org/lkml/2017/4/4/225) fix your issue?
>
> This definitely solves the issue!
>
> Since this fixes broken backlight (that, in turn, makes systems unusable),
> perhaps this should be included in the next rc cycle?

You mean v4.11 final, as there probably won't be another rc?
Yes!

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
--
To unsubscribe from this list: send the line "unsubscribe linux-pwm" in
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Paul Kocialkowski April 18, 2017, 8:46 a.m.
Hi,

Le lundi 17 avril 2017 à 21:36 +0200, Geert Uytterhoeven a écrit :
> On Mon, Apr 17, 2017 at 5:38 PM, Paul Kocialkowski <contact@paulk.fr> wrote:
> > Le dimanche 16 avril 2017 à 22:55 +0200, Geert Uytterhoeven a écrit :
> > > On Sun, Apr 16, 2017 at 12:35 PM, Paul Kocialkowski <contact@paulk.fr>
> > > wrote:
> > > > The move to a dedicated pwm_backlight_initial_power_state function in
> > > > commit 7613c922315e308a6486d802abed2eb74443dffd modified the condition
> > > > to set the enable gpio as output. This breaks specific use cases using
> > > > that GPIO, such as tegra124-based nyan Chromebooks where backlight
> > > > stopped working.
> > > > 
> > > > This puts the condition back to the way it was before the move.
> > > > 
> > > > Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
> > > 
> > > Does "[PATCH v2] backlight: pwm_bl: Fix GPIO out for unimplemented
> > > .get_direction()"
> > > (https://lkml.org/lkml/2017/4/4/225) fix your issue?
> > 
> > This definitely solves the issue!
> > 
> > Since this fixes broken backlight (that, in turn, makes systems unusable),
> > perhaps this should be included in the next rc cycle?
> 
> You mean v4.11 final, as there probably won't be another rc?
> Yes!

I'm all for it!

Cheers,
Daniel Thompson April 20, 2017, 9:55 a.m.
On 18/04/17 09:46, Paul Kocialkowski wrote:
> Hi,
>
> Le lundi 17 avril 2017 à 21:36 +0200, Geert Uytterhoeven a écrit :
>> On Mon, Apr 17, 2017 at 5:38 PM, Paul Kocialkowski <contact@paulk.fr> wrote:
>>> Le dimanche 16 avril 2017 à 22:55 +0200, Geert Uytterhoeven a écrit :
>>>> On Sun, Apr 16, 2017 at 12:35 PM, Paul Kocialkowski <contact@paulk.fr>
>>>> wrote:
>>>>> The move to a dedicated pwm_backlight_initial_power_state function in
>>>>> commit 7613c922315e308a6486d802abed2eb74443dffd modified the condition
>>>>> to set the enable gpio as output. This breaks specific use cases using
>>>>> that GPIO, such as tegra124-based nyan Chromebooks where backlight
>>>>> stopped working.
>>>>>
>>>>> This puts the condition back to the way it was before the move.
>>>>>
>>>>> Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
>>>>
>>>> Does "[PATCH v2] backlight: pwm_bl: Fix GPIO out for unimplemented
>>>> .get_direction()"
>>>> (https://lkml.org/lkml/2017/4/4/225) fix your issue?
>>>
>>> This definitely solves the issue!
>>>
>>> Since this fixes broken backlight (that, in turn, makes systems unusable),
>>> perhaps this should be included in the next rc cycle?
>>
>> You mean v4.11 final, as there probably won't be another rc?
>> Yes!
>
> I'm all for it!

Thanks for keeping our attention on this. I sent a PR yesterday (and 
hope my GPG key has attracted enough signatures).


Daniel.
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Geert Uytterhoeven April 20, 2017, 10:16 a.m.
Hi Daniel,

On Thu, Apr 20, 2017 at 11:55 AM, Daniel Thompson
<daniel.thompson@linaro.org> wrote:
> On 18/04/17 09:46, Paul Kocialkowski wrote:
>> Le lundi 17 avril 2017 à 21:36 +0200, Geert Uytterhoeven a écrit :
>>> On Mon, Apr 17, 2017 at 5:38 PM, Paul Kocialkowski <contact@paulk.fr>
>>> wrote:
>>>> Le dimanche 16 avril 2017 à 22:55 +0200, Geert Uytterhoeven a écrit :
>>>>> On Sun, Apr 16, 2017 at 12:35 PM, Paul Kocialkowski <contact@paulk.fr>
>>>>> wrote:
>>>>>>
>>>>>> The move to a dedicated pwm_backlight_initial_power_state function in
>>>>>> commit 7613c922315e308a6486d802abed2eb74443dffd modified the condition
>>>>>> to set the enable gpio as output. This breaks specific use cases using
>>>>>> that GPIO, such as tegra124-based nyan Chromebooks where backlight
>>>>>> stopped working.
>>>>>>
>>>>>> This puts the condition back to the way it was before the move.
>>>>>>
>>>>>> Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
>>>>>
>>>>> Does "[PATCH v2] backlight: pwm_bl: Fix GPIO out for unimplemented
>>>>> .get_direction()"
>>>>> (https://lkml.org/lkml/2017/4/4/225) fix your issue?
>>>>
>>>> This definitely solves the issue!
>>>>
>>>> Since this fixes broken backlight (that, in turn, makes systems
>>>> unusable),
>>>> perhaps this should be included in the next rc cycle?
>>>
>>> You mean v4.11 final, as there probably won't be another rc?
>>> Yes!
>>
>> I'm all for it!
>
> Thanks for keeping our attention on this. I sent a PR yesterday (and hope my
> GPG key has attracted enough signatures).

Thank you, this morning I had already noticed it went upstream.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
--
To unsubscribe from this list: send the line "unsubscribe linux-pwm" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Paul Kocialkowski April 22, 2017, 1 p.m.
Hi,

Le jeudi 20 avril 2017 à 10:55 +0100, Daniel Thompson a écrit :
> On 18/04/17 09:46, Paul Kocialkowski wrote:
> > Hi,
> > 
> > Le lundi 17 avril 2017 à 21:36 +0200, Geert Uytterhoeven a écrit :
> > > On Mon, Apr 17, 2017 at 5:38 PM, Paul Kocialkowski <contact@paulk.fr>
> > > wrote:
> > > > Le dimanche 16 avril 2017 à 22:55 +0200, Geert Uytterhoeven a écrit :
> > > > > On Sun, Apr 16, 2017 at 12:35 PM, Paul Kocialkowski <contact@paulk.fr>
> > > > > wrote:
> > > > > > The move to a dedicated pwm_backlight_initial_power_state function
> > > > > > in
> > > > > > commit 7613c922315e308a6486d802abed2eb74443dffd modified the
> > > > > > condition
> > > > > > to set the enable gpio as output. This breaks specific use cases
> > > > > > using
> > > > > > that GPIO, such as tegra124-based nyan Chromebooks where backlight
> > > > > > stopped working.
> > > > > > 
> > > > > > This puts the condition back to the way it was before the move.
> > > > > > 
> > > > > > Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
> > > > > 
> > > > > Does "[PATCH v2] backlight: pwm_bl: Fix GPIO out for unimplemented
> > > > > .get_direction()"
> > > > > (https://lkml.org/lkml/2017/4/4/225) fix your issue?
> > > > 
> > > > This definitely solves the issue!
> > > > 
> > > > Since this fixes broken backlight (that, in turn, makes systems
> > > > unusable),
> > > > perhaps this should be included in the next rc cycle?
> > > 
> > > You mean v4.11 final, as there probably won't be another rc?
> > > Yes!
> > 
> > I'm all for it!
> 
> Thanks for keeping our attention on this. I sent a PR yesterday (and 
> hope my GPG key has attracted enough signatures).

Thanks for acting fast and getting this merged already. This is greatly
appreciated!

Cheers,

Patch hide | download patch | download mbox

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index d7efcb632f7d..e81b2b55be2b 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -304,7 +304,8 @@  static int pwm_backlight_probe(struct platform_device *pdev)
 	 * early. Leave the decision of the initial backlight state for later.
 	 */
 	if (pb->enable_gpio &&
-	    gpiod_get_direction(pb->enable_gpio) == GPIOF_DIR_IN)
+	   (gpiod_get_direction(pb->enable_gpio) == GPIOF_DIR_IN ||
+	    gpiod_get_value(pb->enable_gpio) != 0))
 		gpiod_direction_output(pb->enable_gpio, 1);
 
 	pb->power_supply = devm_regulator_get(&pdev->dev, "power");