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 04339C4332F for ; Sun, 16 Oct 2022 14:48:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229800AbiJPOsm (ORCPT ); Sun, 16 Oct 2022 10:48:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55828 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229820AbiJPOsY (ORCPT ); Sun, 16 Oct 2022 10:48:24 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CB8913DF34; Sun, 16 Oct 2022 07:48:20 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B02E760B8B; Sun, 16 Oct 2022 14:48:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D29FCC433D6; Sun, 16 Oct 2022 14:48:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1665931699; bh=PwswarpIsnAjgn6DfCntn7yraIl65QxAItg0kQxGTlY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=WZPnuy+px4WNDcb0Fgzmb0494nU6lBk+0lEFRfgU4oArL4d8fCSzRisSvzQSlBK9r VQLi61JCOMqLHCtoG/F3M3TnsYzuPIjLK8bJmnZTPr/EelLWk6Cp7TbIFlz5t74y21 6HHhZJygjvzc32fl0NwHV6qQ7pscFFeWA5AzLk+833cZZg4V0y+wU8rNQHwFL5R3a6 9SSouj+8sqXXaqQ4LwdHHNjZY6Teeioo7yQIcLKonlyC9lWVpkrozr0KR/EU6rWt4+ Rzo8xJ+icu/ErkLFvexJ+QF1V7w21lRlWhLxliSbNxWyq2nlKytx0PFdk64/dU9UzT Ijqu/Nfz6p05g== Date: Sun, 16 Oct 2022 10:48:17 -0400 From: Sasha Levin To: Hans de Goede Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, "Rafael J . Wysocki" , Arvid Norlander , rafael@kernel.org, linux-acpi@vger.kernel.org Subject: Re: [PATCH AUTOSEL 4.14 4/6] ACPI: video: Change disable_backlight_sysfs_if quirks to acpi_backlight=native Message-ID: References: <20221009235808.1232269-1-sashal@kernel.org> <20221009235808.1232269-4-sashal@kernel.org> <610e3232-d66c-cac3-b13d-ec8b24a1de6e@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <610e3232-d66c-cac3-b13d-ec8b24a1de6e@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Mon, Oct 10, 2022 at 09:37:16AM +0200, Hans de Goede wrote: >Hi, > >On 10/10/22 01:58, Sasha Levin wrote: >> From: Hans de Goede >> >> [ Upstream commit c5b94f5b7819348c59f9949b2b75c341a114cdd4 ] >> >> Some Toshibas have a broken acpi-video interface for brightness control >> and need a special firmware call on resume to turn the panel back on. >> So far these have been using the disable_backlight_sysfs_if workaround >> to deal with this. >> >> The recent x86/acpi backlight refactoring has broken this workaround: >> 1. This workaround relies on acpi_video_get_backlight_type() returning >> acpi_video so that the acpi_video code actually runs; and >> 2. this relies on the actual native GPU driver to offer the sysfs >> backlight interface to userspace. >> >> After the refactor this breaks since the native driver will no >> longer register its backlight-device if acpi_video_get_backlight_type() >> does not return native and making it return native breaks 1. >> >> Keeping the acpi_video backlight handling on resume active, while not >> using it to set the brightness, is necessary because it does a _BCM >> call on resume which is necessary to turn the panel back on on resume. >> >> Looking at the DSDT shows that this _BCM call results in a Toshiba >> HCI_SET HCI_LCD_BRIGHTNESS call, which turns the panel back on. >> >> This kind of special vendor specific handling really belongs in >> the vendor specific acpi driver. An earlier patch in this series >> modifies toshiba_acpi to make the necessary HCI_SET call on resume >> on affected models. >> >> With toshiba_acpi taking care of the HCI_SET call on resume, >> the acpi_video code no longer needs to call _BCM on resume. >> >> So instead of using the (now broken) disable_backlight_sysfs_if >> workaround, simply setting acpi_backlight=native to disable >> the broken apci-video interface is sufficient fix things now. >> >> After this there are no more users of the disable_backlight_sysfs_if >> flag and as discussed above the flag also no longer works as intended, >> so remove the disable_backlight_sysfs_if flag entirely. >> >> Acked-by: Rafael J. Wysocki >> Tested-by: Arvid Norlander >> Signed-off-by: Hans de Goede >> Signed-off-by: Sasha Levin > >This patch goes hand in hand with: > >commit 3cb1f40dfdc3 ("drivers/platform: toshiba_acpi: Call HCI_PANEL_POWER_ON on resume on some models") > >and without that commit also being present it will cause a regression on >the quirked Toshiba models. > >This really is part of the big x86/ACPI backlight handling refactor which >has landed in 6.1 and as such is not intended for older kernels, please >drop this from the stable series. Will do, thanks! -- Thanks, Sasha