From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aaron Lu Subject: Re: [RFC PATCH 1/2] acpi: video: Allow forcing native backlight on non win8 machines Date: Wed, 04 Mar 2015 10:50:20 +0800 Message-ID: <54F672EC.6010404@intel.com> References: <1425368350-4028-1-git-send-email-hdegoede@redhat.com> <1425368350-4028-2-git-send-email-hdegoede@redhat.com> <54F57018.7000302@intel.com> <54F5B300.7020904@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mga03.intel.com ([134.134.136.65]:53643 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757189AbbCDCv1 (ORCPT ); Tue, 3 Mar 2015 21:51:27 -0500 In-Reply-To: <54F5B300.7020904@redhat.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Hans de Goede , "Rafael J. Wysocki" Cc: Zhang Rui , linux-acpi@vger.kernel.org On 03/03/2015 09:11 PM, Hans de Goede wrote: > Hi, > > On 03-03-15 09:26, Aaron Lu wrote: >> On 03/03/2015 03:39 PM, Hans de Goede wrote: >>> The native backlight behavior (so not registering both the acpi-video and the >>> vendor backlight driver) can be useful on some non win8 machines too, allow >>> the user to force this behavior by passing video.use_native_backlight=2 >>> on the kernel commandline. >> >> Just bikeshedding, what about doing it this way? >> >> In the acpi_video_use_native_backlight function: >> 1 If user has set a cmdline option, use that(no matter if it is a win8 >> system or not); >> 2 If the system is in a DMI table, use that(no matter if it is a win8 >> system or not); >> 3 return true if this is a win8 system; false otherwise. >> >> Something like this: > > That works for me, and has the added advantage of not changing the > cmdline syntax (but it does change the cmdline behavior ...). Oh yes, I didn't consider this. Not sure how much impact this will have, but I don't see an immediate problem with it, so let's see. > > So going either way is fine with me. > > Aaron's version is: > > Acked-by: Hans de Goede Thanks. Here is the full patch: From: Aaron Lu Date: Wed, 4 Mar 2015 10:24:58 +0800 Subject: [PATCH] acpi: video: Allow forcing native backlight on non win8 machines The native backlight behavior (so not registering both the acpi-video and the vendor backlight driver) can be useful on some non win8 machines too, so change the behavior of the video.use_native_backlight=1 or 0 kernel cmdline option to be: if user has set video.use_native_backlight=1 or 0, use that no matter if it is a win8 system or not. Also, we will put some known systems into the DMI table to make them either use native backlight interface or not, so the use_native_backlight_dmi is used to reflect that. Original-by: Hans de Goede Signed-offby: Aaron Lu Acked-by: Hans de Goede --- drivers/acpi/video.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c index debd30917010..4cd0c8a4fd9d 100644 --- a/drivers/acpi/video.c +++ b/drivers/acpi/video.c @@ -84,7 +84,7 @@ module_param(allow_duplicates, bool, 0644); */ static int use_native_backlight_param = -1; module_param_named(use_native_backlight, use_native_backlight_param, int, 0444); -static bool use_native_backlight_dmi = true; +static int use_native_backlight_dmi = -1; static int register_count; static struct mutex video_list_lock; @@ -239,13 +239,14 @@ static bool acpi_video_use_native_backlight(void) { if (use_native_backlight_param != -1) return use_native_backlight_param; - else + else if (use_native_backlight_dmi != -1) return use_native_backlight_dmi; + return acpi_osi_is_win8(); } bool acpi_video_verify_backlight_support(void) { - if (acpi_osi_is_win8() && acpi_video_use_native_backlight() && + if (acpi_video_use_native_backlight() && backlight_device_registered(BACKLIGHT_RAW)) return false; return acpi_video_backlight_support(); @@ -414,7 +415,7 @@ static int __init video_set_bqc_offset(const struct dmi_system_id *d) static int __init video_disable_native_backlight(const struct dmi_system_id *d) { - use_native_backlight_dmi = false; + use_native_backlight_dmi = 0; return 0; } -- 2.1.0