Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755899Ab1D3K12 (ORCPT ); Sat, 30 Apr 2011 06:27:28 -0400 Received: from cantor.suse.de ([195.135.220.2]:46493 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755518Ab1D3K10 (ORCPT ); Sat, 30 Apr 2011 06:27:26 -0400 Date: Sat, 30 Apr 2011 12:27:24 +0200 Message-ID: From: Takashi Iwai To: Melchior FRANZ Cc: Linus Torvalds , linux-kernel@vger.kernel.org, Chris Wilson , dri-devel@lists.freedesktop.org Subject: Re: i915/kms/backlight-combo mode problem (was: Re: Linux 2.6.39-rc5) In-Reply-To: <201104301032.05271@rk-nord.at> References: <201104292209.55154@rk-nord.at> <201104301032.05271@rk-nord.at> User-Agent: Wanderlust/2.15.6 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.7 Emacs/23.2 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2818 Lines: 89 At Sat, 30 Apr 2011 10:32:04 +0200, Melchior FRANZ wrote: > > * Takashi Iwai -- Saturday 30 April 2011: > > I remember vaguely that the value zero could be interpreted as the max. > > > Also, with the patch, does the backlight level can be adjusted > > correctly to different values? I wonder whether LBPC adjustment > > really works or not on your machine. > > > + if (!lbpc) > > + lbpc = 0xff; /* max value */ > > This change does *not* work on my machine. The screen stays black > again. Hrm, then it's really hard to say how exactly the system behaves when lbpc=0... I guess we should avoid controlling LBPC in such a case, e.g. something like the patch below (totally untested). But Intel guys must know of this better... I leave this to their hands. > > Yes, backlight adjustment generally works on this notebook, but only > with "acpi_osi=Linux" on the command line. acpi_osi quirk should be better added statically, then. thanks, Takashi --- diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 1c1b27c..c0ab771 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -328,6 +328,7 @@ typedef struct drm_i915_private { struct intel_overlay *overlay; /* LVDS info */ + int backlight_combination_mode; /* 0=unknown, -1=no, 1=yes */ int backlight_level; /* restore backlight to this value */ bool backlight_enabled; struct drm_display_mode *panel_fixed_mode; diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c index a06ff07..320dd5f 100644 --- a/drivers/gpu/drm/i915/intel_panel.c +++ b/drivers/gpu/drm/i915/intel_panel.c @@ -115,14 +115,24 @@ done: static int is_backlight_combination_mode(struct drm_device *dev) { struct drm_i915_private *dev_priv = dev->dev_private; - - if (INTEL_INFO(dev)->gen >= 4) - return I915_READ(BLC_PWM_CTL2) & BLM_COMBINATION_MODE; - - if (IS_GEN2(dev)) - return I915_READ(BLC_PWM_CTL) & BLM_LEGACY_MODE; - - return 0; + int combo_mode; + u8 lbpc; + + if (dev_priv->backlight_combination_mode) + return dev_priv->backlight_combination_mode > 0; + + pci_read_config_byte(dev->pdev, PCI_LBPC, &lbpc); + if (!lbpc) + combo_mode = 0; + else if (INTEL_INFO(dev)->gen >= 4) + combo_mode = I915_READ(BLC_PWM_CTL2) & BLM_COMBINATION_MODE; + else if (IS_GEN2(dev)) + combo_mode = I915_READ(BLC_PWM_CTL) & BLM_LEGACY_MODE; + else + combo_mode = 0; + + dev_priv->backlight_combination_mode = combo_mode ? -1 : 1; + return combo_mode; } static u32 i915_read_blc_pwm_ctl(struct drm_i915_private *dev_priv) -- 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/