From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aaron Lu Subject: Re: ACPI/i915: Cannot configure display brightness on Dell Latitude E6440 Date: Thu, 25 Sep 2014 11:15:35 +0800 Message-ID: <542388D7.1010008@intel.com> References: <201409232206.02819@pali> <201409241453.46756@pali> <5422D66D.6090903@redhat.com> <201409242021.10107@pali> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <201409242021.10107@pali> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: =?windows-1252?Q?Pali_Roh=E1r?= , Hans de Goede Cc: David Airlie , Daniel Vetter , intel-gfx@lists.freedesktop.org, "Rafael J. Wysocki" , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, dri-devel@lists.freedesktop.org, Zhang Rui , Len Brown List-Id: dri-devel@lists.freedesktop.org Hi Hans, Thanks for following up and explaining the situation to Pali. On 09/25/2014 02:21 AM, Pali Roh=E1r 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=3Dvendor = > 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/i= ntel_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 *d= ev, 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 a= nd + * 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; +} + static u32 asle_set_backlight(struct drm_device *dev, u32 bclp) { struct drm_i915_private *dev_priv =3D dev->dev_private; @@ -404,11 +422,7 @@ static u32 asle_set_backlight(struct drm_device *dev, = u32 bclp) = DRM_DEBUG_DRIVER("bclp =3D 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; }