From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lukasz Majewski Subject: Re: [PATCH v2 RESEND] video: backlight: pwm_bl: Initialize fb_bl_on[x] and use_count during pwm_backlight_probe() Date: Tue, 3 Jan 2017 00:54:52 +0100 Message-ID: <20170103005452.33d4b117@jawa> References: <1477169904-14997-1-git-send-email-l.majewski@majess.pl> <1482790896-29202-1-git-send-email-l.majewski@majess.pl> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; boundary="Sig_/fMrRwDv5HRq/.IzEZ.MUZJJ"; protocol="application/pgp-signature" Return-path: Received: from 10.mo3.mail-out.ovh.net ([87.98.165.232]:57831 "EHLO 10.mo3.mail-out.ovh.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756719AbdACAfE (ORCPT ); Mon, 2 Jan 2017 19:35:04 -0500 Received: from player771.ha.ovh.net (b9.ovh.net [213.186.33.59]) by mo3.mail-out.ovh.net (Postfix) with ESMTP id 4532B6D5E0 for ; Tue, 3 Jan 2017 00:55:12 +0100 (CET) In-Reply-To: <1482790896-29202-1-git-send-email-l.majewski@majess.pl> Sender: linux-pwm-owner@vger.kernel.org List-Id: linux-pwm@vger.kernel.org To: Thierry Reding , Lee Jones , linux-pwm@vger.kernel.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, Jingoo Han Cc: Liu Ying , Fabio Estevam , Fabio Estevam , Tomi Valkeinen --Sig_/fMrRwDv5HRq/.IzEZ.MUZJJ Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Dear All, A gentle ping for this patch :-) We had a discussion about it in a following thread: http://patchwork.ozlabs.org/patch/689786/ According to comments, I've prepared v2 of this commit and also resend it recently: http://patchwork.ozlabs.org/patch/708844/ Any new comments? Thanks in advance, =C5=81ukasz Majewski > The commit a55944ca82d2=20 > ("backlight: update bd state & fb_blank properties when necessary") > has posed some extra restrictions on blanking and unblanking frame > buffer device. >=20 > Unfortunately, pwm_bl driver's probe did not initialize members of > struct backlight_device necessary for further blank/unblank operation. >=20 > This code in case of initial unblank of backlight device (default=20 > 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). >=20 > 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. >=20 > Signed-off-by: Lukasz Majewski > --- > The patch has been tested on i.MX6q with vanilla 4.9 kernel. > It applies on 4.10-rc1. > --- > drivers/video/backlight/pwm_bl.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) >=20 > 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 =3D FB_BLANK_UNBLANK; > struct pwm_args pargs; > - int ret; > + int ret, i; > =20 > if (!data) { > ret =3D pwm_backlight_parse_dt(&pdev->dev, &defdata); > @@ -348,6 +348,14 @@ static int pwm_backlight_probe(struct > platform_device *pdev)=20 > bl->props.brightness =3D data->dft_brightness; > bl->props.power =3D initial_blank; > + > + if (initial_blank =3D=3D FB_BLANK_UNBLANK) { > + for (i =3D 0; i < FB_MAX; i++) > + bl->fb_bl_on[i] =3D true; > + > + bl->use_count =3D 1; > + } > + > backlight_update_status(bl); > =20 > platform_set_drvdata(pdev, bl); --Sig_/fMrRwDv5HRq/.IzEZ.MUZJJ Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iEYEARECAAYFAlhq6FMACgkQf9/hG2YwgjEKJQCgkppXhM/FER7argZ+MQ1+nI3W gJgAniEzToFDO9/e4mPeOewJipg2ukJ+ =Zeol -----END PGP SIGNATURE----- --Sig_/fMrRwDv5HRq/.IzEZ.MUZJJ--