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 31E42FA3744 for ; Thu, 27 Oct 2022 12:17:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234698AbiJ0MRO (ORCPT ); Thu, 27 Oct 2022 08:17:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50390 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234375AbiJ0MRM (ORCPT ); Thu, 27 Oct 2022 08:17:12 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2B9509FFC for ; Thu, 27 Oct 2022 05:17:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1666873030; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nNSQHBPSHJEe/PSS7iMw1xD+BezXUHkmeN0CFT7EetY=; b=eEiqvbOPirEEnq9tkzdrEgRQ4Ufswx5A45iiZUS2yjK0uwdjNnSrrRCOsqECk8TjiYBif7 05MZMGWi4ZvEPLj//HflT24KWDJC+HEXJcxImC+iHZSictqacI0Ssla2E2jGpU77gLTbee hUvp7+u3VvcuuDO/wWLY5QxZtNsv2Nc= Received: from mail-ej1-f72.google.com (mail-ej1-f72.google.com [209.85.218.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-632-RuX9ulzhN0CxStc_u2pL-A-1; Thu, 27 Oct 2022 08:17:09 -0400 X-MC-Unique: RuX9ulzhN0CxStc_u2pL-A-1 Received: by mail-ej1-f72.google.com with SMTP id gt15-20020a1709072d8f00b007aaac7973fbso901768ejc.23 for ; Thu, 27 Oct 2022 05:17:09 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=nNSQHBPSHJEe/PSS7iMw1xD+BezXUHkmeN0CFT7EetY=; b=Sy8gJl4gug0GlPw1Enr5l9ZhrmItEDd497rwuR7IjEAe6IBXgLmCwIKjLhz/xIvW51 eSCAkAIfT8zUb0MAd78zMhp42iRAR0S+zlosDmnux606Hyzdo2xqbincQ3nTLuxjqFlR Ay7ThOIDEJ+KfPYJHqoPSGotGkIjX5iJNZhlLqNhRRvAgbLELvvPpFmOiiDDHKTdCHLq is8HtOdvI+0G1cmBcQz1zjVRSGiV5ewE3W+soVYm4H1aRLANEoI633c5idwIN00NwZlI zo04z+KTAQVWoxf3A4KKmw6apMtoF6+TNYbdXlrQVfyyLLrieVULVHAnXkbBMMqvx2eR YTAw== X-Gm-Message-State: ACrzQf3ADhVSmPB5iKKH6j2Pw/ViFE+IQJ5QxxTBvTn6SrFxAhpUVVhE WzeNcp7Qpto9ifbV2+84AkCzQiAH8KCoVAkZxSvfK9aeS2NqwDLgFYm1qOOhJ69PhDJdKVwiqXF tdhtVjYcwVjjB0bVe4V44eA== X-Received: by 2002:a17:907:60d3:b0:78d:f874:3267 with SMTP id hv19-20020a17090760d300b0078df8743267mr41647590ejc.409.1666873028250; Thu, 27 Oct 2022 05:17:08 -0700 (PDT) X-Google-Smtp-Source: AMsMyM5kUJ8EV+Zs2dQ2kNzThHLFb2/0/6HQPEpmjy0US3opwfZNp14T88TCVeiHIyLkRkgiys3h2w== X-Received: by 2002:a17:907:60d3:b0:78d:f874:3267 with SMTP id hv19-20020a17090760d300b0078df8743267mr41647570ejc.409.1666873028031; Thu, 27 Oct 2022 05:17:08 -0700 (PDT) Received: from ?IPV6:2001:1c00:c1e:bf00:d69d:5353:dba5:ee81? (2001-1c00-0c1e-bf00-d69d-5353-dba5-ee81.cable.dynamic.v6.ziggo.nl. [2001:1c00:c1e:bf00:d69d:5353:dba5:ee81]) by smtp.gmail.com with ESMTPSA id m2-20020a50ef02000000b00461c375d88csm858104eds.97.2022.10.27.05.17.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 27 Oct 2022 05:17:07 -0700 (PDT) Message-ID: <526db9ed-bc39-b6be-c977-d4509ce22152@redhat.com> Date: Thu, 27 Oct 2022 14:17:06 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.3.1 Subject: Re: [PATCH v5 02/31] drm/i915: Don't register backlight when another backlight should be used (v2) Content-Language: en-US, nl To: "Rafael J. Wysocki" 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 , 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 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> From: Hans de Goede In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Hi, On 10/27/22 14:09, Rafael J. Wysocki wrote: > 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? Right, that can be used as a quick workaround, but we really do want this to work OOTB everywhere. Regards, Hans 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 A46F2FA3743 for ; Thu, 27 Oct 2022 12:17:25 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 942A910E5F3; Thu, 27 Oct 2022 12:17:15 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by gabe.freedesktop.org (Postfix) with ESMTPS id 5766110E5F2 for ; Thu, 27 Oct 2022 12:17:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1666873030; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nNSQHBPSHJEe/PSS7iMw1xD+BezXUHkmeN0CFT7EetY=; b=eEiqvbOPirEEnq9tkzdrEgRQ4Ufswx5A45iiZUS2yjK0uwdjNnSrrRCOsqECk8TjiYBif7 05MZMGWi4ZvEPLj//HflT24KWDJC+HEXJcxImC+iHZSictqacI0Ssla2E2jGpU77gLTbee hUvp7+u3VvcuuDO/wWLY5QxZtNsv2Nc= Received: from mail-ej1-f71.google.com (mail-ej1-f71.google.com [209.85.218.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-648-9siBf0rxNMW19YTL3-BW1Q-1; Thu, 27 Oct 2022 08:17:09 -0400 X-MC-Unique: 9siBf0rxNMW19YTL3-BW1Q-1 Received: by mail-ej1-f71.google.com with SMTP id nc4-20020a1709071c0400b0078a5ceb571bso911472ejc.4 for ; Thu, 27 Oct 2022 05:17:09 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=nNSQHBPSHJEe/PSS7iMw1xD+BezXUHkmeN0CFT7EetY=; b=TCBG3GnAXoJcV6m5zlFsRjcDBpckACTbEDdMQM3gdse1LDuctnLDNMgYEA983Cl/Jg 8R7030218tVmX/Iv3Y33jQFcDrEQEdNS9Hqt2NmunXFV+RA1JAxU7XGvx07gxd6Mgqi+ MRvggMFGa49Rcw0EE7i5LVSDRVpNbYLlnAPHx6GQYmmUDgN7zZ6s1G2zPS3NTMvWcSUc NGcd3FbDci7Ty0BtKU7ukBXePtBL+58qdaJCbKvaeceGFWDw7KCLCP+k9apHT+RDjLNA 342VtYM78wBS9qVkj23t3qFeU2741JLOLzQkEVC6W4swr1xrOniSKfkI45itfzH481AU vbGw== X-Gm-Message-State: ACrzQf23bzr7PxBtfVS2BSEmPuug2HIIueCrjgwg3V+pt4DMYbt2vxLc 0buh/HnUb90Xl5YXwfzsQ+2TSU2kJI7V22xM5Av+R5Wt1Zw5IMgUj1oR4phJI2MyJUJHmELCGq2 sp+unsIhdvAd9VaDQhjHfOmaSTw== X-Received: by 2002:a17:907:60d3:b0:78d:f874:3267 with SMTP id hv19-20020a17090760d300b0078df8743267mr41647599ejc.409.1666873028258; Thu, 27 Oct 2022 05:17:08 -0700 (PDT) X-Google-Smtp-Source: AMsMyM5kUJ8EV+Zs2dQ2kNzThHLFb2/0/6HQPEpmjy0US3opwfZNp14T88TCVeiHIyLkRkgiys3h2w== X-Received: by 2002:a17:907:60d3:b0:78d:f874:3267 with SMTP id hv19-20020a17090760d300b0078df8743267mr41647570ejc.409.1666873028031; Thu, 27 Oct 2022 05:17:08 -0700 (PDT) Received: from ?IPV6:2001:1c00:c1e:bf00:d69d:5353:dba5:ee81? (2001-1c00-0c1e-bf00-d69d-5353-dba5-ee81.cable.dynamic.v6.ziggo.nl. [2001:1c00:c1e:bf00:d69d:5353:dba5:ee81]) by smtp.gmail.com with ESMTPSA id m2-20020a50ef02000000b00461c375d88csm858104eds.97.2022.10.27.05.17.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 27 Oct 2022 05:17:07 -0700 (PDT) Message-ID: <526db9ed-bc39-b6be-c977-d4509ce22152@redhat.com> Date: Thu, 27 Oct 2022 14:17:06 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.3.1 To: "Rafael J. Wysocki" 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> From: Hans de Goede In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US, nl Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit 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 , 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" Hi, On 10/27/22 14:09, Rafael J. Wysocki wrote: > 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? Right, that can be used as a quick workaround, but we really do want this to work OOTB everywhere. Regards, Hans 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 A7B4BFA3742 for ; Thu, 27 Oct 2022 12:17:16 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id C9C0210E5EE; Thu, 27 Oct 2022 12:17:14 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by gabe.freedesktop.org (Postfix) with ESMTPS id 775E810E5F3 for ; Thu, 27 Oct 2022 12:17:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1666873030; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nNSQHBPSHJEe/PSS7iMw1xD+BezXUHkmeN0CFT7EetY=; b=eEiqvbOPirEEnq9tkzdrEgRQ4Ufswx5A45iiZUS2yjK0uwdjNnSrrRCOsqECk8TjiYBif7 05MZMGWi4ZvEPLj//HflT24KWDJC+HEXJcxImC+iHZSictqacI0Ssla2E2jGpU77gLTbee hUvp7+u3VvcuuDO/wWLY5QxZtNsv2Nc= Received: from mail-ej1-f70.google.com (mail-ej1-f70.google.com [209.85.218.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-622-sQ6OHezmNoaUDT27DslKNA-1; Thu, 27 Oct 2022 08:17:09 -0400 X-MC-Unique: sQ6OHezmNoaUDT27DslKNA-1 Received: by mail-ej1-f70.google.com with SMTP id xh12-20020a170906da8c00b007413144e87fso901354ejb.14 for ; Thu, 27 Oct 2022 05:17:09 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=nNSQHBPSHJEe/PSS7iMw1xD+BezXUHkmeN0CFT7EetY=; b=MwWam6rpncUlaixTfABRiaCG3vOjk3n3sMoFWux2+0kGwwycwwTUPBNm39/lSFCJGP b0pXrqYSXztuq6G6XwvJryLwA630bUcZuo/Uaa3W3lN2dMf2oSEQp/Dn6e7dl3lQRFxr cMumTy7OHp+E5MusMp8ovetS6WBcb2hmnN9mA/4J8OjvP2TjAeMI9psHPTLWw8gS5NYT 4zKFeyJjuZYCjv7ZhhChzwjhXdsWmaiS2UY1Ix0y/TD4WUjpK5GKFVkha7ekliiNEnfE h8HkOUBTKr+x8ruUdwk5RSQ1eNuviFdckwX4rnmSx/oZPL0csoHCDFFmm+8L9JXTMoZF z0Qw== X-Gm-Message-State: ACrzQf2623FGRAwasjj/WQjEhBpusoaHd2hv+oJm6KcjM2XNXBpD+qVf vwxNyL3/cjLV+6Vu+ELCKQs/Ilgm0E1UqQh1IoQwc09NHwaAMsHKdD8kp0NNMCTOHwpz12HajaE eKx5taHzvdgVuOXXoSCgiMTxrJIva X-Received: by 2002:a17:907:60d3:b0:78d:f874:3267 with SMTP id hv19-20020a17090760d300b0078df8743267mr41647610ejc.409.1666873028280; Thu, 27 Oct 2022 05:17:08 -0700 (PDT) X-Google-Smtp-Source: AMsMyM5kUJ8EV+Zs2dQ2kNzThHLFb2/0/6HQPEpmjy0US3opwfZNp14T88TCVeiHIyLkRkgiys3h2w== X-Received: by 2002:a17:907:60d3:b0:78d:f874:3267 with SMTP id hv19-20020a17090760d300b0078df8743267mr41647570ejc.409.1666873028031; Thu, 27 Oct 2022 05:17:08 -0700 (PDT) Received: from ?IPV6:2001:1c00:c1e:bf00:d69d:5353:dba5:ee81? (2001-1c00-0c1e-bf00-d69d-5353-dba5-ee81.cable.dynamic.v6.ziggo.nl. [2001:1c00:c1e:bf00:d69d:5353:dba5:ee81]) by smtp.gmail.com with ESMTPSA id m2-20020a50ef02000000b00461c375d88csm858104eds.97.2022.10.27.05.17.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 27 Oct 2022 05:17:07 -0700 (PDT) Message-ID: <526db9ed-bc39-b6be-c977-d4509ce22152@redhat.com> Date: Thu, 27 Oct 2022 14:17:06 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.3.1 Subject: Re: [PATCH v5 02/31] drm/i915: Don't register backlight when another backlight should be used (v2) To: "Rafael J. Wysocki" 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> From: Hans de Goede In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US, nl Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit 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 , 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" Hi, On 10/27/22 14:09, Rafael J. Wysocki wrote: > 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? Right, that can be used as a quick workaround, but we really do want this to work OOTB everywhere. Regards, Hans 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 D60ABECAAA1 for ; Thu, 27 Oct 2022 12:17:28 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6F07110E5F2; Thu, 27 Oct 2022 12:17:15 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by gabe.freedesktop.org (Postfix) with ESMTPS id AB0FA10E5F4 for ; Thu, 27 Oct 2022 12:17:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1666873030; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nNSQHBPSHJEe/PSS7iMw1xD+BezXUHkmeN0CFT7EetY=; b=eEiqvbOPirEEnq9tkzdrEgRQ4Ufswx5A45iiZUS2yjK0uwdjNnSrrRCOsqECk8TjiYBif7 05MZMGWi4ZvEPLj//HflT24KWDJC+HEXJcxImC+iHZSictqacI0Ssla2E2jGpU77gLTbee hUvp7+u3VvcuuDO/wWLY5QxZtNsv2Nc= Received: from mail-ej1-f72.google.com (mail-ej1-f72.google.com [209.85.218.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-540-nb_wmW93ODGinhWEJBERKQ-1; Thu, 27 Oct 2022 08:17:09 -0400 X-MC-Unique: nb_wmW93ODGinhWEJBERKQ-1 Received: by mail-ej1-f72.google.com with SMTP id sd8-20020a1709076e0800b007ac2e1693abso902043ejc.13 for ; Thu, 27 Oct 2022 05:17:09 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=nNSQHBPSHJEe/PSS7iMw1xD+BezXUHkmeN0CFT7EetY=; b=bSf5sOLbXM45NOOwcQnZS47UTzEeWWTRkIIUDK3UkBsIRyB5E0V1zUp67jnqObswl1 xNYuQ2o6UaezbJF5osmvRrGa4nY7LFBt2gmiOxKVF+Wz6DkLAHLdmOwHs9Rsdc2aStgz sN2xnQZ0mxEPO8EfzB6q15r5BsjzN5EnN9T2SNWYvCAbsSzznf8QA5B2kCXcGacHBSxl ZqdPnUS3lu6G+eRF00sxoma1Gcf2i2Z70/AAHUbhRF1ZD1Xlqr3qSJo5QCRJuURh5Msl opDNMD9TbkDCn7g1CxGRX617U46NOod43P/IW3u6SIjZSgsD04YK66VYzu9XGnuEgNtH 2qiw== X-Gm-Message-State: ACrzQf2jsKIBZdb/W36HhMUQfCJGez4DWvBtbqFKeMw8jOxZnDHsKNE2 p5/v/7kiarjK6si5Ej+H8ulGywyQeMJvO4e+AJvtUlYlhxxWkHNgrqavN2aDh7JyC2wh3hQEfT8 1nVVFB3F43FGjgI9Vdeodhvf5kbft X-Received: by 2002:a17:907:60d3:b0:78d:f874:3267 with SMTP id hv19-20020a17090760d300b0078df8743267mr41647585ejc.409.1666873028244; Thu, 27 Oct 2022 05:17:08 -0700 (PDT) X-Google-Smtp-Source: AMsMyM5kUJ8EV+Zs2dQ2kNzThHLFb2/0/6HQPEpmjy0US3opwfZNp14T88TCVeiHIyLkRkgiys3h2w== X-Received: by 2002:a17:907:60d3:b0:78d:f874:3267 with SMTP id hv19-20020a17090760d300b0078df8743267mr41647570ejc.409.1666873028031; Thu, 27 Oct 2022 05:17:08 -0700 (PDT) Received: from ?IPV6:2001:1c00:c1e:bf00:d69d:5353:dba5:ee81? (2001-1c00-0c1e-bf00-d69d-5353-dba5-ee81.cable.dynamic.v6.ziggo.nl. [2001:1c00:c1e:bf00:d69d:5353:dba5:ee81]) by smtp.gmail.com with ESMTPSA id m2-20020a50ef02000000b00461c375d88csm858104eds.97.2022.10.27.05.17.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 27 Oct 2022 05:17:07 -0700 (PDT) Message-ID: <526db9ed-bc39-b6be-c977-d4509ce22152@redhat.com> Date: Thu, 27 Oct 2022 14:17:06 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.3.1 To: "Rafael J. Wysocki" 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> From: Hans de Goede In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US, nl Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit 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 , 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" Hi, On 10/27/22 14:09, Rafael J. Wysocki wrote: > 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? Right, that can be used as a quick workaround, but we really do want this to work OOTB everywhere. 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(2001-1c00-0c1e-bf00-d69d-5353-dba5-ee81.cable.dynamic.v6.ziggo.nl. [2001:1c00:c1e:bf00:d69d:5353:dba5:ee81]) by smtp.gmail.com with ESMTPSA id m2-20020a50ef02000000b00461c375d88csm858104eds.97.2022.10.27.05.17.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 27 Oct 2022 05:17:07 -0700 (PDT) Message-ID: <526db9ed-bc39-b6be-c977-d4509ce22152@redhat.com> Date: Thu, 27 Oct 2022 14:17:06 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.3.1 Subject: Re: [PATCH v5 02/31] drm/i915: Don't register backlight when another backlight should be used (v2) To: "Rafael J. Wysocki" 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> From: Hans de Goede In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US, nl Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Mailman-Approved-At: Thu, 27 Oct 2022 12:33:43 +0000 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 , 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" Hi, On 10/27/22 14:09, Rafael J. Wysocki wrote: > 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? Right, that can be used as a quick workaround, but we really do want this to work OOTB everywhere. Regards, Hans