From: Lukasz Majewski <l.majewski@majess.pl>
To: Lee Jones <lee.jones@linaro.org>
Cc: Thierry Reding <thierry.reding@gmail.com>,
Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>,
Tomi Valkeinen <tomi.valkeinen@ti.com>,
linux-pwm@vger.kernel.org, linux-kernel@vger.kernel.org,
Fabio Estevam <fabio.estevam@nxp.com>,
Fabio Estevam <festevam@gmail.com>,
linux-fbdev@vger.kernel.org, Liu Ying <Ying.Liu@freescale.com>
Subject: Re: [PATCH v2] video: backlight: pwm_bl: Initialize fb_bl_on[x] and use_count during pwm_backlight_probe()
Date: Fri, 11 Nov 2016 00:20:30 +0100 [thread overview]
Message-ID: <20161111002030.6e97ba6c@jawa> (raw)
In-Reply-To: <20161110081615.GO13127@dell>
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Dear Lee,
> On Tue, 08 Nov 2016, Lukasz Majewski wrote:
>
> > Dear All,
> >
> > > The commit a55944ca82d2 ("backlight: update bd state & fb_blank
> > > properties when necessary") has posed some extra restrictions on
> > > blanking and unblanking frame buffer device.
> > >
> > > Unfortunately, pwm_bl driver's probe did not initialize members of
> > > struct backlight_device necessary for further blank/unblank
> > > operation.
> > >
> > > This code in case of initial unblank of backlight device (default
> > > behaviour) sets use_count to 1 and marks this particular backlight
> > > device as used by all available fb devices (since it is not known
> > > during probe how much and which fb devices will be assigned).
> > >
> > > Without this code, the backlight works properly until one tries to
> > > blank it manually from sysfs with "echo 1
> > > > /sys/class/graphics/fb0/blank". Since fb_bl_on[0] and use_count
> > > > were both set to 0, the logic at
> > > fb_notifier_callback (@backlight.c) thought that we didn't turn on
> > > (unblanked) the backlight device and refuses to disable (blank)
> > > it. As a result we see garbage from fb displayed.
> >
> > COmments/acks are more than welcome :-)
>
> Ah, it looks like you dropped Jingoo from the list!
>
I can only apologize for such situation.... strange mistake.
> I'll reply to the original mail with him in CC.
Thank you for your help.
Best regards,
Lukasz Majewski
>
> > > Signed-off-by: Lukasz Majewski <l.majewski@majess.pl>
> > > ---
> > > The patch has been tested on i.MX6q with 4.9-rc3
> > > SHA1: a909d3e636995ba7c349e2ca5dbb528154d4ac30
> > > ---
> > > Changes for v2:
> > > - Update commit message with proper other commit reference
> > >
> > > ---
> > > drivers/video/backlight/pwm_bl.c | 10 +++++++++-
> > > 1 file changed, 9 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/video/backlight/pwm_bl.c
> > > b/drivers/video/backlight/pwm_bl.c index 1261400..6859ba0 100644
> > > --- a/drivers/video/backlight/pwm_bl.c
> > > +++ b/drivers/video/backlight/pwm_bl.c
> > > @@ -202,7 +202,7 @@ static int pwm_backlight_probe(struct
> > > platform_device *pdev) struct pwm_bl_data *pb;
> > > int initial_blank = FB_BLANK_UNBLANK;
> > > struct pwm_args pargs;
> > > - int ret;
> > > + int ret, i;
> > >
> > > if (!data) {
> > > ret = pwm_backlight_parse_dt(&pdev->dev,
> > > &defdata); @@ -348,6 +348,14 @@ static int
> > > pwm_backlight_probe(struct platform_device *pdev)
> > > bl->props.brightness = data->dft_brightness;
> > > bl->props.power = initial_blank;
> > > +
> > > + if (initial_blank == FB_BLANK_UNBLANK) {
> > > + for (i = 0; i < FB_MAX; i++)
> > > + bl->fb_bl_on[i] = true;
> > > +
> > > + bl->use_count = 1;
> > > + }
> > > +
> > > backlight_update_status(bl);
> > >
> > > platform_set_drvdata(pdev, bl);
> >
>
>
>
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next prev parent reply other threads:[~2016-11-10 23:21 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-22 20:58 [PATCH] video: backlight: pwm_bl: Initialize fb_bl_on[x] and use_count during pwm_backlight_probe() Lukasz Majewski
2016-10-24 2:34 ` Jingoo Han
2016-10-24 21:00 ` Lukasz Majewski
2016-10-25 22:47 ` Jingoo Han
2016-10-27 3:46 ` Lukasz Majewski
2016-11-01 7:25 ` [PATCH v2] " Lukasz Majewski
2016-11-08 22:25 ` Lukasz Majewski
2016-11-09 14:52 ` Lee Jones
2016-11-09 21:05 ` Lukasz Majewski
2016-11-10 7:47 ` Lee Jones
2016-11-10 8:16 ` Lee Jones
2016-11-10 23:20 ` Lukasz Majewski [this message]
2016-11-10 8:16 ` Lee Jones
2016-12-26 22:21 ` [PATCH v2 RESEND] " Lukasz Majewski
2017-01-02 23:54 ` Lukasz Majewski
2017-01-03 8:30 ` Lee Jones
2017-01-06 12:29 ` Lukasz Majewski
2017-01-13 0:27 ` Lukasz Majewski
2017-01-23 0:50 ` Lukasz Majewski
2017-01-23 16:09 ` Thierry Reding
2017-01-24 9:37 ` Lee Jones
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