From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753361AbaIZCVA (ORCPT ); Thu, 25 Sep 2014 22:21:00 -0400 Received: from mga03.intel.com ([134.134.136.65]:49866 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752913AbaIZCU5 (ORCPT ); Thu, 25 Sep 2014 22:20:57 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,602,1406617200"; d="scan'208";a="579243446" Message-ID: <5424CD81.2030305@intel.com> Date: Fri, 26 Sep 2014 10:20:49 +0800 From: Aaron Lu MIME-Version: 1.0 To: "Rafael J. Wysocki" CC: =?windows-1252?Q?Pali_Roh=E1r?= , Hans de Goede , "Rafael J. Wysocki" , Zhang Rui , Len Brown , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, Daniel Vetter , Jani Nikula , David Airlie , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Subject: Re: ACPI/i915: Cannot configure display brightness on Dell Latitude E6440 References: <201409232206.02819@pali> <201409242021.10107@pali> <542388D7.1010008@intel.com> <1481425.msp1jP3vqe@vostro.rjw.lan> In-Reply-To: <1481425.msp1jP3vqe@vostro.rjw.lan> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/26/2014 03:58 AM, Rafael J. Wysocki wrote: > On Thursday, September 25, 2014 11:15:35 AM Aaron Lu wrote: >> Hi Hans, >> >> Thanks for following up and explaining the situation to Pali. >> >> On 09/25/2014 02:21 AM, Pali Rohár wrote: >>> On Wednesday 24 September 2014 16:34:21 Hans de Goede wrote: >>>> Ok, so the dell-laptop interface is just an obsolete wrapper >>>> around the i915 opregion code, which shows that the right >>>> interface to use is the i915 one, which we do if you don't >>>> specify any kernel commandline parameters, case closed. >>>> >>>> Regards, >>>> >>>> Hans >>> >>> Nope, its not closed. >>> >>> Still i915 interface has problem with setting backlight. It >>> exports lot of levels which turning display off. Which breaking >>> exiting applications for configuring display brightness. This is >>> still big regression as black screen is not want people want to >>> see. >>> >>> Driver dell-laptop has exported only few - not thousands level >>> (which is insane) and only usefull levels (not lot of levels >>> which turn display off). >>> >>> So for this reason using i915 backlight interface is not possible >>> and also Dell (for E6440) set kernel param acpi_backlight=vendor >>> to use dell_laptop module for controlling brightness. >>> >>> On my laptop E6440 is better for using dell-laptop and not acpi >>> or i915. >> >> Hi Pali, >> >> Please test this patch: >> >> diff --git a/drivers/gpu/drm/i915/intel_opregion.c b/drivers/gpu/drm/i915/intel_opregion.c >> index ca52ad2ae7d1..15534345bd57 100644 >> --- a/drivers/gpu/drm/i915/intel_opregion.c >> +++ b/drivers/gpu/drm/i915/intel_opregion.c >> @@ -396,6 +396,24 @@ int intel_opregion_notify_adapter(struct drm_device *dev, pci_power_t state) >> return -EINVAL; >> } >> >> +/* >> + * Some of the Thinkpads' firmware will issue a backlight change operation >> + * region request unconditionally on AC plug/unplug, this is undesirable and >> + * should be ignored. Then there is a Dell laptop whose vendor backlight >> + * interface also makes use of operation region request to change backlight >> + * level and we have to keep it work. The rule used here is: if the vendor >> + * backlight interface is not in use and the ACPI backlight interface is >> + * broken, we ignore the requests; oterwise, we keep processing them. >> + */ >> +static bool should_ignore_backlight_request(void) >> +{ >> + if (acpi_video_backlight_support() && >> + !acpi_video_verify_backlight_support()) >> + return true; >> + >> + return false; >> +} > > Well, what about > > return acpi_video_backlight_support() && !acpi_video_verify_backlight_support(); > > ? Yes that's better. Will send out a patch with this change, thanks for the suggestion. -Aaron > >> + >> static u32 asle_set_backlight(struct drm_device *dev, u32 bclp) >> { >> struct drm_i915_private *dev_priv = dev->dev_private; >> @@ -404,11 +422,7 @@ static u32 asle_set_backlight(struct drm_device *dev, u32 bclp) >> >> DRM_DEBUG_DRIVER("bclp = 0x%08x\n", bclp); >> >> - /* >> - * If the acpi_video interface is not supposed to be used, don't >> - * bother processing backlight level change requests from firmware. >> - */ >> - if (!acpi_video_verify_backlight_support()) { >> + if (should_ignore_backlight_request()) { >> DRM_DEBUG_KMS("opregion backlight request ignored\n"); >> return 0; >> } >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> Please read the FAQ at http://www.tux.org/lkml/ >