From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751834Ab2AUWba (ORCPT ); Sat, 21 Jan 2012 17:31:30 -0500 Received: from home.keithp.com ([63.227.221.253]:53670 "EHLO keithp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751306Ab2AUWb3 (ORCPT ); Sat, 21 Jan 2012 17:31:29 -0500 From: Keith Packard To: Chris Diamand Cc: linux-kernel@vger.kernel.org, tiwai@suse.de, melchior.franz@gmail.com Subject: Re: i915/kms/backlight-combo mode problem In-Reply-To: <4F1B2D64.7020705@gmail.com> References: <4F1AF145.2090407@gmail.com> <86k44kkity.fsf@sumi.keithp.com> <4F1B2D64.7020705@gmail.com> User-Agent: Notmuch/0.11 (http://notmuchmail.org) Emacs/23.3.1 (i486-pc-linux-gnu) Date: Sat, 21 Jan 2012 14:31:24 -0800 Message-ID: <86bopwk7r7.fsf@sumi.keithp.com> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-=-= Content-Transfer-Encoding: quoted-printable On Sat, 21 Jan 2012 21:25:56 +0000, Chris Diamand = wrote: > 0x00 is the brightest. It gets very gradually dimmer up to about 0xB0,=20 > when the gaps between > brightness levels are slightly bigger. > 0xFE is very low but still works. > Barely any difference between 0x80 and 0x7f, same with 0x00 and 0x01, > etc. Here's a patch which just flips the interpretation of that value over; does this work? diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/inte= l_panel.c index 04d79fd..43faa9d 100644 =2D-- a/drivers/gpu/drm/i915/intel_panel.c +++ b/drivers/gpu/drm/i915/intel_panel.c @@ -207,6 +207,7 @@ u32 intel_panel_get_backlight(struct drm_device *dev) u8 lbpc; =20 pci_read_config_byte(dev->pdev, PCI_LBPC, &lbpc); + lbpc =3D 0xff - lbpc; val *=3D lbpc; } } @@ -238,7 +239,7 @@ static void intel_panel_actually_set_backlight(struct d= rm_device *dev, u32 level =20 lbpc =3D level * 0xfe / max + 1; level /=3D lbpc; =2D pci_write_config_byte(dev->pdev, PCI_LBPC, lbpc); + pci_write_config_byte(dev->pdev, PCI_LBPC, 0xff - lbpc); } =20 tmp =3D I915_READ(BLC_PWM_CTL); =2D-=20 keith.packard@intel.com --=-=-= Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQIVAwUBTxs8vDYtFsjWk68qAQiepw//TnBIPVitHA2vYjNfDa3W8m7S5YmT5tPF 8CXAawOOUyT+fU+pxRJ18FeZF0JmYGKj+NiDV3A8GLD1yBKbjUXft8jI0DMXwW2F YmC5KPpRkJsSAaQHLZahGl//BmT1vLlY58yeOf624G7qLN9cH9XgqXOYDIXwrcgw Xa+4cVYbhS3E1iyQ0YYB0u61yUYYacqLBI7z/8y5evSz2hxx9H4PHAsgWVFYby/I KfSjjV0kDt2Tu+lXKrbDm52jXu4xxG46oLCmZDvEzZAh1r+7LijXk1vOUbuf8Imy oydFjV5erE+4QR4YoYrqnJP/tT44poED5dX873vzQy/bv1idKVB2JK+m0qNwczVy viipDaQQ1lugaDT1vOrWy7iH8a0biuyDxVBY41qWLz2ypw1UFx8MdOs0/JwfbQUS ykutilhESPV2W21Pw5vBzebImWF5L7LrI7a0a8bn4U83qo7UOJFvL/0ezESRT85K aqr6bG4KjZkHqg360EPXo4+zRKC35dYG10DkRGttoW9DIW97XNtfqe8fmvVGFXS9 cK8UVYwYTRNi1fHLaMB4Q0kHSspcCRsFP0EMEOOQpS3RVqgwTw+E8VR3Z2G4B0gf ypjLpFkdW1aBGOeRn25VDEambS8oMMMr8AiWS1kmre8yIT/N0gVIyQXw6vMAqiI4 u7Ei31cTaRI= =2Eh8 -----END PGP SIGNATURE----- --=-=-=--