From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 111BAFA3742 for ; Thu, 27 Oct 2022 12:09:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234595AbiJ0MJo (ORCPT ); Thu, 27 Oct 2022 08:09:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33228 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235105AbiJ0MJm (ORCPT ); Thu, 27 Oct 2022 08:09:42 -0400 Received: from mail-qk1-f176.google.com (mail-qk1-f176.google.com [209.85.222.176]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3ECA8FD1B; Thu, 27 Oct 2022 05:09:39 -0700 (PDT) Received: by mail-qk1-f176.google.com with SMTP id t25so678514qkm.2; Thu, 27 Oct 2022 05:09:39 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=zob33Kla+RLsm+RvZFRkkpciG4NSOFsYMv+2iMSvbU8=; b=CnFRBN6hqsiJfJbaCHQYVuEvwtRot4dkP0yK/+f0RL2koht3pbZHzKonwcD/JaNR2S HXdvrYNS6/B+VblmqwL7DKtpHpJ4Pt3CJwoXZpqakSKbBO7/bEPwK9snds4ZwiVx5BU4 2Sv7/B0ymXKEZeJZVM3OJPtCAc676k8v5I+rbvhHz68HGnVY4N5qyRC0ohyGnLhgytJF JRm3JCMvP0iCxCeY2EnM7U7KQwV1EH6fK+YmkA/oumpQet4PyeTDOwD4jtNMxDgTufHi i2T7i4g+rbKJcehvqzE/oOCm5aR954HhnzGBGnoLv3KUeDbWBAHZ7+hG+q6paA4H0Lk9 lBLA== X-Gm-Message-State: ACrzQf1njF7lrOrqWZFkDmMnc0FBxemIFKV7Otde9LG0PVcNp9h936lw qs+948jlkAdW//Ne+Hl6KsE4ir+MaEJcjkA6UnM= X-Google-Smtp-Source: AMsMyM6NeMFZa4GPKFIdb5StMWZOoUw58iXZAY6R77ZAJLEXASKkFV1w1vtNejdRxPCAyFXWVssLUx0L9nTXahQ4MDI= X-Received: by 2002:a05:620a:4626:b0:6ee:b43:d2bc with SMTP id br38-20020a05620a462600b006ee0b43d2bcmr32868704qkb.764.1666872578327; Thu, 27 Oct 2022 05:09:38 -0700 (PDT) MIME-Version: 1.0 References: <20221025193248.GA21457@srcf.ucam.org> <144cd47e-42dc-2b84-1a90-ea5e080e08a3@redhat.com> <20221025204043.GA23306@srcf.ucam.org> <20221025234040.GA27673@srcf.ucam.org> <20221026204920.GA15326@srcf.ucam.org> <099dee98-8aeb-af36-828c-110f5ac6e9a3@redhat.com> <20221027091123.GA28089@srcf.ucam.org> <933be908-0bc2-56cc-8d6f-38f2d208ef20@redhat.com> <20221027095249.GA28666@srcf.ucam.org> <6df2016d-ed2d-57fa-dcad-48537732895f@redhat.com> In-Reply-To: <6df2016d-ed2d-57fa-dcad-48537732895f@redhat.com> From: "Rafael J. Wysocki" Date: Thu, 27 Oct 2022 14:09:27 +0200 Message-ID: Subject: Re: [PATCH v5 02/31] drm/i915: Don't register backlight when another backlight should be used (v2) To: Hans de Goede Cc: Matthew Garrett , Dmitry Osipenko , Ben Skeggs , Karol Herbst , Lyude , Daniel Dadap , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Tvrtko Ursulin , Alex Deucher , =?UTF-8?Q?Christian_K=C3=B6nig?= , Xinhui , "Rafael J . Wysocki" , Mika Westerberg , Lukas Wunner , Mark Gross , Andy Shevchenko , linux-acpi@vger.kernel.org, Jani Nikula , nouveau@lists.freedesktop.org, intel-gfx , dri-devel@lists.freedesktop.org, platform-driver-x86@vger.kernel.org, amd-gfx@lists.freedesktop.org, David Airlie , Len Brown Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Thu, Oct 27, 2022 at 12:37 PM Hans de Goede wrote: > > Hi, > > On 10/27/22 11:52, Matthew Garrett wrote: > > On Thu, Oct 27, 2022 at 11:39:38AM +0200, Hans de Goede wrote: > > > >> The *only* behavior which actually is new in 6.1 is the native GPU > >> drivers now doing the equivalent of: > >> > >> if (acpi_video_get_backlight_type() != acpi_backlight_native) > >> return; > >> > >> In their backlight register paths (i), which is causing the native > >> backlight to disappear on your custom laptop setup and on Chromebooks > >> (with the Chromebooks case being already solved I hope.). > > > > It's causing the backlight control to vanish on any machine that isn't > > ((acpi_video || vendor interface) || !acpi). Most machines that fall > > into that are either weird or Chromebooks or old, but there are machines > > that fall into that. > > I acknowledge that their are machines that fall into this category, > but I expect / hope there to be so few of them that we can just DMI > quirk our way out if this. > > I believe the old group to be small because: > > 1. Generally speaking the "native" control method is usually not > present on the really old (pre ACPI video spec) mobile GPUs. > > 2. On most old laptops I would still expect there to be a vendor > interface too, and if both get registered standard desktop environments > will prefer the vendor one, so then we need a native DMI quirk to > disable the vendor interface anyways and we already have a bunch of > those, so some laptops in this group are already covered by DMI quirks. > > And a fix for the Chromebook case is already in Linus' tree, which > just leaves the weird case, of which there will hopefully be only > a few. > > I do share your worry that this might break some machines, but > the only way to really find out is to get this code out there > I'm afraid. > > I have just written a blog post asking for people to check if > their laptop might be affected; and to report various details > to me of their laptop is affected: > > https://hansdegoede.dreamwidth.org/26548.html > > Lets wait and see how this goes. If I get (too) many reports then > I will send a revert of the addition of the: > > if (acpi_video_get_backlight_type() != acpi_backlight_native) > return; > > check to the i915 / radeon / amd / nouveau drivers. > > (And if I only get a couple of reports I will probably just submit > DMI quirks for the affected models). Sounds reasonable to me, FWIW. And IIUC the check above can be overridden by passing acpi_backlight=native in the kernel command line, right? From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 02D6EFA3744 for ; Thu, 27 Oct 2022 12:09:54 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0BED610E5EE; Thu, 27 Oct 2022 12:09:45 +0000 (UTC) Received: from mail-qk1-f170.google.com (mail-qk1-f170.google.com [209.85.222.170]) by gabe.freedesktop.org (Postfix) with ESMTPS id 52AC110E5E6; Thu, 27 Oct 2022 12:09:39 +0000 (UTC) Received: by mail-qk1-f170.google.com with SMTP id t25so678515qkm.2; Thu, 27 Oct 2022 05:09:39 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=zob33Kla+RLsm+RvZFRkkpciG4NSOFsYMv+2iMSvbU8=; b=c6nvfMWCKTy6m6KpiK9dvSPTbHBH/5CFWHmz9e+GiyVgcCNMtGNu2h16uCsi+jIEdb 1hRSq76zNWT2Xxaxiv5c1a50y8yn7gzK85rBX3YlNsHstdt0KtWFZFkCO70WwYxSVJbY o7bFgLypZmRRSjVE+8gzoDeaVf5SuulW6XJ5/Nt8dmi+6YnhPQZ13EP8mEigWE2jqXXl mya5PTXIpImzt5q+ruL7/QDlNAtAJbACzZjJ6RB2eq0ZxQLNr77kC8J7VKDmEa2z2yt/ r6SqsEd96e6wMUiRMcUCA9+n1eYnN2vGA0QfKH20H0tcHB2j2MIt6JxVVzs5k7tFI1Pv cdFA== X-Gm-Message-State: ACrzQf3WhPZUdqv0HGhupM2ZqWmYJEdRkA3hffF1+a9YJeQloSYASKaz uqMeYa2WZUBgKqeRhxX3O+KDVuwrei5P+re7ho8= X-Google-Smtp-Source: AMsMyM6NeMFZa4GPKFIdb5StMWZOoUw58iXZAY6R77ZAJLEXASKkFV1w1vtNejdRxPCAyFXWVssLUx0L9nTXahQ4MDI= X-Received: by 2002:a05:620a:4626:b0:6ee:b43:d2bc with SMTP id br38-20020a05620a462600b006ee0b43d2bcmr32868704qkb.764.1666872578327; Thu, 27 Oct 2022 05:09:38 -0700 (PDT) MIME-Version: 1.0 References: <20221025193248.GA21457@srcf.ucam.org> <144cd47e-42dc-2b84-1a90-ea5e080e08a3@redhat.com> <20221025204043.GA23306@srcf.ucam.org> <20221025234040.GA27673@srcf.ucam.org> <20221026204920.GA15326@srcf.ucam.org> <099dee98-8aeb-af36-828c-110f5ac6e9a3@redhat.com> <20221027091123.GA28089@srcf.ucam.org> <933be908-0bc2-56cc-8d6f-38f2d208ef20@redhat.com> <20221027095249.GA28666@srcf.ucam.org> <6df2016d-ed2d-57fa-dcad-48537732895f@redhat.com> In-Reply-To: <6df2016d-ed2d-57fa-dcad-48537732895f@redhat.com> From: "Rafael J. Wysocki" Date: Thu, 27 Oct 2022 14:09:27 +0200 Message-ID: To: Hans de Goede Content-Type: text/plain; charset="UTF-8" Subject: Re: [Nouveau] [PATCH v5 02/31] drm/i915: Don't register backlight when another backlight should be used (v2) X-BeenThere: nouveau@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Nouveau development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Daniel Dadap , nouveau@lists.freedesktop.org, Joonas Lahtinen , dri-devel@lists.freedesktop.org, platform-driver-x86@vger.kernel.org, Dmitry Osipenko , "Rafael J . Wysocki" , amd-gfx@lists.freedesktop.org, linux-acpi@vger.kernel.org, Ben Skeggs , David Airlie , Len Brown , Jani Nikula , intel-gfx , Maarten Lankhorst , Jani Nikula , Mark Gross , Maxime Ripard , Rodrigo Vivi , Mika Westerberg , Andy Shevchenko , Tvrtko Ursulin , Xinhui , Alex Deucher , =?UTF-8?Q?Christian_K=C3=B6nig?= Errors-To: nouveau-bounces@lists.freedesktop.org Sender: "Nouveau" On Thu, Oct 27, 2022 at 12:37 PM Hans de Goede wrote: > > Hi, > > On 10/27/22 11:52, Matthew Garrett wrote: > > On Thu, Oct 27, 2022 at 11:39:38AM +0200, Hans de Goede wrote: > > > >> The *only* behavior which actually is new in 6.1 is the native GPU > >> drivers now doing the equivalent of: > >> > >> if (acpi_video_get_backlight_type() != acpi_backlight_native) > >> return; > >> > >> In their backlight register paths (i), which is causing the native > >> backlight to disappear on your custom laptop setup and on Chromebooks > >> (with the Chromebooks case being already solved I hope.). > > > > It's causing the backlight control to vanish on any machine that isn't > > ((acpi_video || vendor interface) || !acpi). Most machines that fall > > into that are either weird or Chromebooks or old, but there are machines > > that fall into that. > > I acknowledge that their are machines that fall into this category, > but I expect / hope there to be so few of them that we can just DMI > quirk our way out if this. > > I believe the old group to be small because: > > 1. Generally speaking the "native" control method is usually not > present on the really old (pre ACPI video spec) mobile GPUs. > > 2. On most old laptops I would still expect there to be a vendor > interface too, and if both get registered standard desktop environments > will prefer the vendor one, so then we need a native DMI quirk to > disable the vendor interface anyways and we already have a bunch of > those, so some laptops in this group are already covered by DMI quirks. > > And a fix for the Chromebook case is already in Linus' tree, which > just leaves the weird case, of which there will hopefully be only > a few. > > I do share your worry that this might break some machines, but > the only way to really find out is to get this code out there > I'm afraid. > > I have just written a blog post asking for people to check if > their laptop might be affected; and to report various details > to me of their laptop is affected: > > https://hansdegoede.dreamwidth.org/26548.html > > Lets wait and see how this goes. If I get (too) many reports then > I will send a revert of the addition of the: > > if (acpi_video_get_backlight_type() != acpi_backlight_native) > return; > > check to the i915 / radeon / amd / nouveau drivers. > > (And if I only get a couple of reports I will probably just submit > DMI quirks for the affected models). Sounds reasonable to me, FWIW. And IIUC the check above can be overridden by passing acpi_backlight=native in the kernel command line, right? From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B95A0ECAAA1 for ; Thu, 27 Oct 2022 12:09:44 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4B74E10E5E6; Thu, 27 Oct 2022 12:09:42 +0000 (UTC) Received: from mail-qk1-f170.google.com (mail-qk1-f170.google.com [209.85.222.170]) by gabe.freedesktop.org (Postfix) with ESMTPS id 52AC110E5E6; Thu, 27 Oct 2022 12:09:39 +0000 (UTC) Received: by mail-qk1-f170.google.com with SMTP id t25so678515qkm.2; Thu, 27 Oct 2022 05:09:39 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=zob33Kla+RLsm+RvZFRkkpciG4NSOFsYMv+2iMSvbU8=; b=c6nvfMWCKTy6m6KpiK9dvSPTbHBH/5CFWHmz9e+GiyVgcCNMtGNu2h16uCsi+jIEdb 1hRSq76zNWT2Xxaxiv5c1a50y8yn7gzK85rBX3YlNsHstdt0KtWFZFkCO70WwYxSVJbY o7bFgLypZmRRSjVE+8gzoDeaVf5SuulW6XJ5/Nt8dmi+6YnhPQZ13EP8mEigWE2jqXXl mya5PTXIpImzt5q+ruL7/QDlNAtAJbACzZjJ6RB2eq0ZxQLNr77kC8J7VKDmEa2z2yt/ r6SqsEd96e6wMUiRMcUCA9+n1eYnN2vGA0QfKH20H0tcHB2j2MIt6JxVVzs5k7tFI1Pv cdFA== X-Gm-Message-State: ACrzQf3WhPZUdqv0HGhupM2ZqWmYJEdRkA3hffF1+a9YJeQloSYASKaz uqMeYa2WZUBgKqeRhxX3O+KDVuwrei5P+re7ho8= X-Google-Smtp-Source: AMsMyM6NeMFZa4GPKFIdb5StMWZOoUw58iXZAY6R77ZAJLEXASKkFV1w1vtNejdRxPCAyFXWVssLUx0L9nTXahQ4MDI= X-Received: by 2002:a05:620a:4626:b0:6ee:b43:d2bc with SMTP id br38-20020a05620a462600b006ee0b43d2bcmr32868704qkb.764.1666872578327; Thu, 27 Oct 2022 05:09:38 -0700 (PDT) MIME-Version: 1.0 References: <20221025193248.GA21457@srcf.ucam.org> <144cd47e-42dc-2b84-1a90-ea5e080e08a3@redhat.com> <20221025204043.GA23306@srcf.ucam.org> <20221025234040.GA27673@srcf.ucam.org> <20221026204920.GA15326@srcf.ucam.org> <099dee98-8aeb-af36-828c-110f5ac6e9a3@redhat.com> <20221027091123.GA28089@srcf.ucam.org> <933be908-0bc2-56cc-8d6f-38f2d208ef20@redhat.com> <20221027095249.GA28666@srcf.ucam.org> <6df2016d-ed2d-57fa-dcad-48537732895f@redhat.com> In-Reply-To: <6df2016d-ed2d-57fa-dcad-48537732895f@redhat.com> From: "Rafael J. Wysocki" Date: Thu, 27 Oct 2022 14:09:27 +0200 Message-ID: Subject: Re: [PATCH v5 02/31] drm/i915: Don't register backlight when another backlight should be used (v2) To: Hans de Goede Content-Type: text/plain; charset="UTF-8" X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Karol Herbst , Daniel Dadap , nouveau@lists.freedesktop.org, dri-devel@lists.freedesktop.org, platform-driver-x86@vger.kernel.org, Dmitry Osipenko , "Rafael J . Wysocki" , amd-gfx@lists.freedesktop.org, linux-acpi@vger.kernel.org, Ben Skeggs , David Airlie , Len Brown , Matthew Garrett , Jani Nikula , intel-gfx , Mark Gross , Rodrigo Vivi , Mika Westerberg , Andy Shevchenko , Tvrtko Ursulin , Xinhui , Thomas Zimmermann , Alex Deucher , =?UTF-8?Q?Christian_K=C3=B6nig?= Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Thu, Oct 27, 2022 at 12:37 PM Hans de Goede wrote: > > Hi, > > On 10/27/22 11:52, Matthew Garrett wrote: > > On Thu, Oct 27, 2022 at 11:39:38AM +0200, Hans de Goede wrote: > > > >> The *only* behavior which actually is new in 6.1 is the native GPU > >> drivers now doing the equivalent of: > >> > >> if (acpi_video_get_backlight_type() != acpi_backlight_native) > >> return; > >> > >> In their backlight register paths (i), which is causing the native > >> backlight to disappear on your custom laptop setup and on Chromebooks > >> (with the Chromebooks case being already solved I hope.). > > > > It's causing the backlight control to vanish on any machine that isn't > > ((acpi_video || vendor interface) || !acpi). Most machines that fall > > into that are either weird or Chromebooks or old, but there are machines > > that fall into that. > > I acknowledge that their are machines that fall into this category, > but I expect / hope there to be so few of them that we can just DMI > quirk our way out if this. > > I believe the old group to be small because: > > 1. Generally speaking the "native" control method is usually not > present on the really old (pre ACPI video spec) mobile GPUs. > > 2. On most old laptops I would still expect there to be a vendor > interface too, and if both get registered standard desktop environments > will prefer the vendor one, so then we need a native DMI quirk to > disable the vendor interface anyways and we already have a bunch of > those, so some laptops in this group are already covered by DMI quirks. > > And a fix for the Chromebook case is already in Linus' tree, which > just leaves the weird case, of which there will hopefully be only > a few. > > I do share your worry that this might break some machines, but > the only way to really find out is to get this code out there > I'm afraid. > > I have just written a blog post asking for people to check if > their laptop might be affected; and to report various details > to me of their laptop is affected: > > https://hansdegoede.dreamwidth.org/26548.html > > Lets wait and see how this goes. If I get (too) many reports then > I will send a revert of the addition of the: > > if (acpi_video_get_backlight_type() != acpi_backlight_native) > return; > > check to the i915 / radeon / amd / nouveau drivers. > > (And if I only get a couple of reports I will probably just submit > DMI quirks for the affected models). Sounds reasonable to me, FWIW. And IIUC the check above can be overridden by passing acpi_backlight=native in the kernel command line, right? From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4D712FA3742 for ; Thu, 27 Oct 2022 12:09:57 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 224FC10E5EF; Thu, 27 Oct 2022 12:09:45 +0000 (UTC) Received: from mail-qk1-f170.google.com (mail-qk1-f170.google.com [209.85.222.170]) by gabe.freedesktop.org (Postfix) with ESMTPS id 52AC110E5E6; Thu, 27 Oct 2022 12:09:39 +0000 (UTC) Received: by mail-qk1-f170.google.com with SMTP id t25so678515qkm.2; Thu, 27 Oct 2022 05:09:39 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=zob33Kla+RLsm+RvZFRkkpciG4NSOFsYMv+2iMSvbU8=; b=c6nvfMWCKTy6m6KpiK9dvSPTbHBH/5CFWHmz9e+GiyVgcCNMtGNu2h16uCsi+jIEdb 1hRSq76zNWT2Xxaxiv5c1a50y8yn7gzK85rBX3YlNsHstdt0KtWFZFkCO70WwYxSVJbY o7bFgLypZmRRSjVE+8gzoDeaVf5SuulW6XJ5/Nt8dmi+6YnhPQZ13EP8mEigWE2jqXXl mya5PTXIpImzt5q+ruL7/QDlNAtAJbACzZjJ6RB2eq0ZxQLNr77kC8J7VKDmEa2z2yt/ r6SqsEd96e6wMUiRMcUCA9+n1eYnN2vGA0QfKH20H0tcHB2j2MIt6JxVVzs5k7tFI1Pv cdFA== X-Gm-Message-State: ACrzQf3WhPZUdqv0HGhupM2ZqWmYJEdRkA3hffF1+a9YJeQloSYASKaz uqMeYa2WZUBgKqeRhxX3O+KDVuwrei5P+re7ho8= X-Google-Smtp-Source: AMsMyM6NeMFZa4GPKFIdb5StMWZOoUw58iXZAY6R77ZAJLEXASKkFV1w1vtNejdRxPCAyFXWVssLUx0L9nTXahQ4MDI= X-Received: by 2002:a05:620a:4626:b0:6ee:b43:d2bc with SMTP id br38-20020a05620a462600b006ee0b43d2bcmr32868704qkb.764.1666872578327; Thu, 27 Oct 2022 05:09:38 -0700 (PDT) MIME-Version: 1.0 References: <20221025193248.GA21457@srcf.ucam.org> <144cd47e-42dc-2b84-1a90-ea5e080e08a3@redhat.com> <20221025204043.GA23306@srcf.ucam.org> <20221025234040.GA27673@srcf.ucam.org> <20221026204920.GA15326@srcf.ucam.org> <099dee98-8aeb-af36-828c-110f5ac6e9a3@redhat.com> <20221027091123.GA28089@srcf.ucam.org> <933be908-0bc2-56cc-8d6f-38f2d208ef20@redhat.com> <20221027095249.GA28666@srcf.ucam.org> <6df2016d-ed2d-57fa-dcad-48537732895f@redhat.com> In-Reply-To: <6df2016d-ed2d-57fa-dcad-48537732895f@redhat.com> From: "Rafael J. Wysocki" Date: Thu, 27 Oct 2022 14:09:27 +0200 Message-ID: To: Hans de Goede Content-Type: text/plain; charset="UTF-8" Subject: Re: [Intel-gfx] [PATCH v5 02/31] drm/i915: Don't register backlight when another backlight should be used (v2) X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Karol Herbst , Daniel Dadap , nouveau@lists.freedesktop.org, dri-devel@lists.freedesktop.org, platform-driver-x86@vger.kernel.org, Dmitry Osipenko , "Rafael J . Wysocki" , amd-gfx@lists.freedesktop.org, linux-acpi@vger.kernel.org, Ben Skeggs , David Airlie , Len Brown , Jani Nikula , intel-gfx , Mark Gross , Maxime Ripard , Rodrigo Vivi , Mika Westerberg , Andy Shevchenko , Xinhui , Thomas Zimmermann , Alex Deucher , =?UTF-8?Q?Christian_K=C3=B6nig?= Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Thu, Oct 27, 2022 at 12:37 PM Hans de Goede wrote: > > Hi, > > On 10/27/22 11:52, Matthew Garrett wrote: > > On Thu, Oct 27, 2022 at 11:39:38AM +0200, Hans de Goede wrote: > > > >> The *only* behavior which actually is new in 6.1 is the native GPU > >> drivers now doing the equivalent of: > >> > >> if (acpi_video_get_backlight_type() != acpi_backlight_native) > >> return; > >> > >> In their backlight register paths (i), which is causing the native > >> backlight to disappear on your custom laptop setup and on Chromebooks > >> (with the Chromebooks case being already solved I hope.). > > > > It's causing the backlight control to vanish on any machine that isn't > > ((acpi_video || vendor interface) || !acpi). Most machines that fall > > into that are either weird or Chromebooks or old, but there are machines > > that fall into that. > > I acknowledge that their are machines that fall into this category, > but I expect / hope there to be so few of them that we can just DMI > quirk our way out if this. > > I believe the old group to be small because: > > 1. Generally speaking the "native" control method is usually not > present on the really old (pre ACPI video spec) mobile GPUs. > > 2. On most old laptops I would still expect there to be a vendor > interface too, and if both get registered standard desktop environments > will prefer the vendor one, so then we need a native DMI quirk to > disable the vendor interface anyways and we already have a bunch of > those, so some laptops in this group are already covered by DMI quirks. > > And a fix for the Chromebook case is already in Linus' tree, which > just leaves the weird case, of which there will hopefully be only > a few. > > I do share your worry that this might break some machines, but > the only way to really find out is to get this code out there > I'm afraid. > > I have just written a blog post asking for people to check if > their laptop might be affected; and to report various details > to me of their laptop is affected: > > https://hansdegoede.dreamwidth.org/26548.html > > Lets wait and see how this goes. If I get (too) many reports then > I will send a revert of the addition of the: > > if (acpi_video_get_backlight_type() != acpi_backlight_native) > return; > > check to the i915 / radeon / amd / nouveau drivers. > > (And if I only get a couple of reports I will probably just submit > DMI quirks for the affected models). Sounds reasonable to me, FWIW. And IIUC the check above can be overridden by passing acpi_backlight=native in the kernel command line, right? From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id EE539FA3743 for ; Thu, 27 Oct 2022 12:09:52 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id D06EC10E5ED; Thu, 27 Oct 2022 12:09:42 +0000 (UTC) Received: from mail-qk1-f170.google.com (mail-qk1-f170.google.com [209.85.222.170]) by gabe.freedesktop.org (Postfix) with ESMTPS id 52AC110E5E6; Thu, 27 Oct 2022 12:09:39 +0000 (UTC) Received: by mail-qk1-f170.google.com with SMTP id t25so678515qkm.2; Thu, 27 Oct 2022 05:09:39 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=zob33Kla+RLsm+RvZFRkkpciG4NSOFsYMv+2iMSvbU8=; b=c6nvfMWCKTy6m6KpiK9dvSPTbHBH/5CFWHmz9e+GiyVgcCNMtGNu2h16uCsi+jIEdb 1hRSq76zNWT2Xxaxiv5c1a50y8yn7gzK85rBX3YlNsHstdt0KtWFZFkCO70WwYxSVJbY o7bFgLypZmRRSjVE+8gzoDeaVf5SuulW6XJ5/Nt8dmi+6YnhPQZ13EP8mEigWE2jqXXl mya5PTXIpImzt5q+ruL7/QDlNAtAJbACzZjJ6RB2eq0ZxQLNr77kC8J7VKDmEa2z2yt/ r6SqsEd96e6wMUiRMcUCA9+n1eYnN2vGA0QfKH20H0tcHB2j2MIt6JxVVzs5k7tFI1Pv cdFA== X-Gm-Message-State: ACrzQf3WhPZUdqv0HGhupM2ZqWmYJEdRkA3hffF1+a9YJeQloSYASKaz uqMeYa2WZUBgKqeRhxX3O+KDVuwrei5P+re7ho8= X-Google-Smtp-Source: AMsMyM6NeMFZa4GPKFIdb5StMWZOoUw58iXZAY6R77ZAJLEXASKkFV1w1vtNejdRxPCAyFXWVssLUx0L9nTXahQ4MDI= X-Received: by 2002:a05:620a:4626:b0:6ee:b43:d2bc with SMTP id br38-20020a05620a462600b006ee0b43d2bcmr32868704qkb.764.1666872578327; Thu, 27 Oct 2022 05:09:38 -0700 (PDT) MIME-Version: 1.0 References: <20221025193248.GA21457@srcf.ucam.org> <144cd47e-42dc-2b84-1a90-ea5e080e08a3@redhat.com> <20221025204043.GA23306@srcf.ucam.org> <20221025234040.GA27673@srcf.ucam.org> <20221026204920.GA15326@srcf.ucam.org> <099dee98-8aeb-af36-828c-110f5ac6e9a3@redhat.com> <20221027091123.GA28089@srcf.ucam.org> <933be908-0bc2-56cc-8d6f-38f2d208ef20@redhat.com> <20221027095249.GA28666@srcf.ucam.org> <6df2016d-ed2d-57fa-dcad-48537732895f@redhat.com> In-Reply-To: <6df2016d-ed2d-57fa-dcad-48537732895f@redhat.com> From: "Rafael J. Wysocki" Date: Thu, 27 Oct 2022 14:09:27 +0200 Message-ID: Subject: Re: [PATCH v5 02/31] drm/i915: Don't register backlight when another backlight should be used (v2) To: Hans de Goede Content-Type: text/plain; charset="UTF-8" X-BeenThere: amd-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussion list for AMD gfx List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Karol Herbst , Daniel Dadap , nouveau@lists.freedesktop.org, Joonas Lahtinen , dri-devel@lists.freedesktop.org, platform-driver-x86@vger.kernel.org, Dmitry Osipenko , "Rafael J . Wysocki" , amd-gfx@lists.freedesktop.org, linux-acpi@vger.kernel.org, Ben Skeggs , David Airlie , Len Brown , Matthew Garrett , Jani Nikula , intel-gfx , Maarten Lankhorst , Jani Nikula , Mark Gross , Maxime Ripard , Rodrigo Vivi , Mika Westerberg , Andy Shevchenko , Tvrtko Ursulin , Xinhui , Lukas Wunner , Thomas Zimmermann , Alex Deucher , =?UTF-8?Q?Christian_K=C3=B6nig?= Errors-To: amd-gfx-bounces@lists.freedesktop.org Sender: "amd-gfx" On Thu, Oct 27, 2022 at 12:37 PM Hans de Goede wrote: > > Hi, > > On 10/27/22 11:52, Matthew Garrett wrote: > > On Thu, Oct 27, 2022 at 11:39:38AM +0200, Hans de Goede wrote: > > > >> The *only* behavior which actually is new in 6.1 is the native GPU > >> drivers now doing the equivalent of: > >> > >> if (acpi_video_get_backlight_type() != acpi_backlight_native) > >> return; > >> > >> In their backlight register paths (i), which is causing the native > >> backlight to disappear on your custom laptop setup and on Chromebooks > >> (with the Chromebooks case being already solved I hope.). > > > > It's causing the backlight control to vanish on any machine that isn't > > ((acpi_video || vendor interface) || !acpi). Most machines that fall > > into that are either weird or Chromebooks or old, but there are machines > > that fall into that. > > I acknowledge that their are machines that fall into this category, > but I expect / hope there to be so few of them that we can just DMI > quirk our way out if this. > > I believe the old group to be small because: > > 1. Generally speaking the "native" control method is usually not > present on the really old (pre ACPI video spec) mobile GPUs. > > 2. On most old laptops I would still expect there to be a vendor > interface too, and if both get registered standard desktop environments > will prefer the vendor one, so then we need a native DMI quirk to > disable the vendor interface anyways and we already have a bunch of > those, so some laptops in this group are already covered by DMI quirks. > > And a fix for the Chromebook case is already in Linus' tree, which > just leaves the weird case, of which there will hopefully be only > a few. > > I do share your worry that this might break some machines, but > the only way to really find out is to get this code out there > I'm afraid. > > I have just written a blog post asking for people to check if > their laptop might be affected; and to report various details > to me of their laptop is affected: > > https://hansdegoede.dreamwidth.org/26548.html > > Lets wait and see how this goes. If I get (too) many reports then > I will send a revert of the addition of the: > > if (acpi_video_get_backlight_type() != acpi_backlight_native) > return; > > check to the i915 / radeon / amd / nouveau drivers. > > (And if I only get a couple of reports I will probably just submit > DMI quirks for the affected models). Sounds reasonable to me, FWIW. And IIUC the check above can be overridden by passing acpi_backlight=native in the kernel command line, right?