From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757206Ab2COHYt (ORCPT ); Thu, 15 Mar 2012 03:24:49 -0400 Received: from mail.gw90.de ([188.40.100.199]:57892 "EHLO mail.gw90.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751187Ab2COHYr (ORCPT ); Thu, 15 Mar 2012 03:24:47 -0400 Message-ID: <1331796281.3718.10.camel@mattotaupa> Subject: Re: [V2 PATCH 2/2] drivers-gpu-drm-i915-invert-backlight-brightness From: Paul Menzel To: Carsten Emde Cc: David Airlie , Valdis Kletnieks , LKML , DRI , Thomas Gleixner Date: Thu, 15 Mar 2012 08:24:41 +0100 In-Reply-To: <20120314234830.227490545@osadl.org> References: <20120314233544.629616190@osadl.org> <20120314234830.227490545@osadl.org> Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="=-hUM2jMyJqjavO5f8CEn7" X-Mailer: Evolution 3.2.2-1 Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-hUM2jMyJqjavO5f8CEn7 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Am Donnerstag, den 15.03.2012, 00:35 +0100 schrieb Carsten Emde: > Einfaches Textdokument-Anlage > (drivers-gpu-drm-i915-invert-backlight-brightness.patch) quilt also does not adapt the subject line of the message correctly to the one of the patch. > Following the documentation of the Legacy Backlight Brightness (LBB) > Register in the configuration space of some Intel PCI graphics adapters, > setting the LBB register with the value 0x0 causes the backlight to be > turned off, and 0xFF causes the backlight to be set to 100% intensity > (http://download.intel.com/embedded/processors/Whitepaper/324567.pdf). > At least one of our test systems, however, turns the backlight off at > 0xFF and sets it to maximum intensity at 0. In consequence, the screen > of this systems becomes dark at an early boot stage which makes it > unusable. The same inversion applies to the BLC_PWM_CTL I915 register. > This problem was introduced in kernel version 2.6.38 when the PCI device > of this system was first supported by the i915 KMS module. >=20 > This patch adds a module parameter to invert the backlight brightness > value before writing and after reading which makes the affected notebook > usable again. >=20 > Signed-off-by: Carsten Emde >=20 > --- > Documentation/kernel-parameters.txt | 9 +++++++++ > drivers/gpu/drm/i915/intel_panel.c | 14 ++++++++++++++ > 2 files changed, 23 insertions(+) >=20 > Index: linux-3.3-rc6/Documentation/kernel-parameters.txt > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > --- linux-3.3-rc6.orig/Documentation/kernel-parameters.txt > +++ linux-3.3-rc6/Documentation/kernel-parameters.txt > @@ -966,6 +966,15 @@ bytes respectively. Such letter suffixes > =20 > i810=3D [HW,DRM] > =20 > + i915.invert_brightness > + [DRM] Invert the sense of the variable that is used to > + set the brightness of the panel backlight. Normally a > + value of 0 indicates backlight switched off, and the > + maximum value sets the backlight to maximum brightness. > + If this parameter is specified, a value of 0 sets the > + backlight to maximum brightness, and the maximum value > + switches the backlight off. > + > i8k.ignore_dmi [HW] Continue probing hardware even if DMI data > indicates that the driver is running on unsupported > hardware. > Index: linux-3.3-rc6/drivers/gpu/drm/i915/intel_panel.c > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > --- linux-3.3-rc6.orig/drivers/gpu/drm/i915/intel_panel.c > +++ linux-3.3-rc6/drivers/gpu/drm/i915/intel_panel.c > @@ -28,6 +28,7 @@ > * Chris Wilson > */ > =20 > +#include > #include "intel_drv.h" > =20 > #define PCI_LBPC 0xf4 /* legacy/combination backlight modes */ > @@ -191,6 +192,10 @@ u32 intel_panel_get_max_backlight(struct > return max; > } > =20 > +static bool brightness_inverted; > +MODULE_PARM_DESC(brightness_inverted, "Backlight brightness value is inv= erted " > + "(0 =3D max brightness, max value =3D dark)"); Could you elaborate somewhere for example by giving an example what `dark` means? As a normal user it is not clear to me. > +module_param_named(brightness_inverted, brightness_inverted, bool, 0600)= ; > u32 intel_panel_get_backlight(struct drm_device *dev) > { > struct drm_i915_private *dev_priv =3D dev->dev_private; > @@ -212,6 +217,10 @@ u32 intel_panel_get_backlight(struct drm > } > =20 > DRM_DEBUG_DRIVER("get backlight PWM =3D %d\n", val); > + if (brightness_inverted) { > + u32 max =3D intel_panel_get_max_backlight(dev); > + val =3D max - val; > + } > return val; > } > =20 > @@ -229,6 +238,11 @@ static void intel_panel_actually_set_bac > =20 > DRM_DEBUG_DRIVER("set backlight PWM =3D %d\n", level); > =20 > + if (brightness_inverted) { > + u32 max =3D intel_panel_get_max_backlight(dev); > + level =3D max - level; > + } > + > if (HAS_PCH_SPLIT(dev)) > return intel_pch_panel_set_backlight(dev, level); Thanks, Paul --=-hUM2jMyJqjavO5f8CEn7 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iEYEABECAAYFAk9hmTkACgkQPX1aK2wOHVgzZgCeP5U80uH++9MJxcWzifBil/zU q5wAoIBp60qq9b71mWyqnoO0nAyX03MA =/+Jl -----END PGP SIGNATURE----- --=-hUM2jMyJqjavO5f8CEn7--