From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=74.125.82.176 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794672581; b=2Lq+45eB+vfPI7R8UzbJ0/wTwjmUGchGUx6Ap2m9JAx10H+xsXcp6qNwUQbuSsrjr0Ur OK3wsorYh2k5gdbkin5QXR3YoaunY8wBY0Z7YoKxcPrs8EsYcgXXibRCulDwBI/9ULDKO 0IbIB/wfNKKFf8av5G99iJS3ZAOX5rbh2Q4aoGW3g4o6Qz9zq68/cK7eCfRkAp5SqhVAK k4t8cRlDWfrdXR16jTzgmF6U40rI3fPXb1uBGEX5NiRqxDFCKPM7N79hhd1rDXfWLm4mG W8hVqK9LPh8VSxvGVco7CobvhUAZUFUK6VQrVS/dv0MmkH7OyxTwfRd+r27ZSOOEhNA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794672581; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Gm-Gg:X-Received:Received: From:To:Cc:Subject:Date:Message-ID:X-Mailer:In-Reply-To:References: MIME-Version:Content-Transfer-Encoding; bh=5Ir5z9ASuMHPvYC0aOx9GZ500HHk9wmpAKRwADGNQH8=; b=N+Rsx4by/vuPy10X/73fPwIna9h4AWKJPasvQbwSlJHOaoKCJjEp0QyMoL+2Dr+5GXpk HGMcD0SWO9TMf99oB6MiCePM5j3t/WE/pUGoEpU9PEwxi0EzUt3GYluKcy4flkejPkoV5 RKyW4hnAdMoMLB2r05DbonQvHFp4c/jjJCk77S0mK/0/g2Et4tCVJZgpozzUHG1px0iwq lxvCGYEyrBPg/zq2Q+HKeueXxPyauhsSbu9syvZjbQ+Tsu6KkyoVHvFUYgTEriinJ13NG ZNHx/aJXNpw1lML5nSYfOj7ljtw1xP+gaD4NdhLdaJ1mMxEb59dj1UGU8z9ZCgvaDMw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20260707 header.b=uIm9AAin; arc=none smtp.remote-ip=74.125.82.176 Received: from mail-dy1-f176.google.com (mail-dy1-f176.google.com [74.125.82.176]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 987B8606A32E for ; Sat, 14 Nov 2026 16:09:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 987B8606A32E Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20260707 header.b=uIm9AAin Received: by mail-dy1-f176.google.com with SMTP id 5a478bee46e88-36f8cdd30beso2135197eec.1 for ; Sat, 14 Nov 2026 08:09:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20260707; t=1794672580; x=1795277380; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=5Ir5z9ASuMHPvYC0aOx9GZ500HHk9wmpAKRwADGNQH8=; b=uIm9AAin37f1DmnmWI/WA9iNizuoMxHTH/ZK/2yI5YNDPtU4tz+Hz3DhfXXM9tWIR4 NusOf9ieQA4sgvFT38yKJChg1gqwaKl66YD+dkdgfbGZgPcN7xPZ6ZU7vCfUcA5H7DUT yH/b7JTtmoCxMMWAFWXI8hcf9C3Enq/IEJzM+OPQ3AU4tp+GTLbSMCCoWL/NC5mv2ENq Ag/GKZrZnJFu3qLClJ3MiEVjZc2D8+EYHNTCER2NauyOsYT6wHTVDVPNM0g5B6vhE7R8 JZJ9xXI77qfuRh/U4Q0WYCg6Eerd6b8o/9MxSpnIvt24SHTVopZmnlqaZkm8kJ1XNv9O 2caA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1794672580; x=1795277380; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=5Ir5z9ASuMHPvYC0aOx9GZ500HHk9wmpAKRwADGNQH8=; b=Z2yej+28RG1QT6QoX2MUNlur7GtcOu6cSYSiJS/BuPGTN9ZwqreFTyKdR1YKjmKqEA /tzzDzEuc7HY4u+bxsQ/nuPj445n3F880tv8PZI6K09RePBCbG1hjClSMiyxHMiYvQZp 80Bb6KPespR0VRouWh+Lj+TQ1u7sXe9AKaWHWR2l7jPYcM6BqhM5tkSGFETPud+ATXIV Ifbsrq3O1v5YR8G1jc2IYtKEyoC0ibjhKoeuPzISpBlZaHc92GUSvCiCvp+UiptHA/Cu ymV4XZbdqBSAyJGLUPEPOid5DBpLnjjZaqvHIuFbVEVCkz904TFmQzefgyyIEpTrPrH5 WuWg== X-Forwarded-Encrypted: i=1; AL+hErHZL2xgWb5gY7x80qpA/aXpZMltn5KTZlME1EgkvFyMmwa4ddKczGGQGCc/tghEsGMhPJUa7J6pIdnZUyk=@vger.kernel.org X-Gm-Message-State: APuU4Z/XKBEylMMjSpq94AizGcpQiV9+66rpZx9qpxSyZi4OrhnA24vG LJmHAmWw6O2NacpmZhHodwbD58tc8elEebIeoRbl21pRbX2RZHSeVig= X-Gm-Gg: AYBFou1yue/uMVEhyccgREkBpcTWz2eRPriUfnsg2LJFv5rK+D9OfsG3KQqzJC7TXJE T3wwyoWJRQKjHiiVhE/+9dCb0U6EEW+WG7L7h+/8ll89Y+1aeGuyHvXloUVmCRD9cDhCxbMU951 Ea2U+379vT/0Cw4CwoAgoLnj6411MWaeb2WuuCN9n1xttwFpApqalstlXjnXJGKRvGwyNzeJmbf /9R5yB6MXc4ckqhihqfHFhjbJhFfvpM5FAgjaWQpX6vFY8Yc83b7jl53VzXpnxgGMRUZgfOYD5N 3cV3WCqx27DdzRUaJR7Dhw+lT5WbUXSqgBkfKJDFWtUudTyMYPO4sFu+Jzr716vNeyVumMusu7w PifKW/Hzy8x42hkGPGf1g7fvW0AuCuc3dLrLvbw9b3zyS8D+DCAmFLwdWV1VphonkiwtaoFzzIA imMzoJT3hkEgkJsSvCXn9fHra3saW3ZoORNb0p03TvKrEmefdxpVUS11hFBzshWr0C4veb4E7Zs W96SIhVNVkDbKcexMHLSKQ5LZgBMmMAr9wDjoHPBlR/klJlXsbosGypYEL+9VIzStZzDPKEz9+O kAQS/Qxf0UV6fpBbwzBbHRIKxZhfxxq8NDhepgVyWH4HrnHU7zVb9mNcj2ynwTz+/T4= X-Received: by 2002:a05:701b:4648:b0:19b:1202:77f8 with SMTP id a92af1059eb24-1b503192303mr5750642c88.32.1794672579670; Sat, 14 Nov 2026 08:09:39 -0800 (PST) Received: from at-Standard-PC-Q35-ICH9-2009 ([106.202.127.108]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-37956bb0919sm17567582eec.29.2026.11.14.08.09.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 14 Nov 2026 08:09:39 -0800 (PST) From: Atharva Tiwari To: Cc: Atharva Tiwari , Sebastian Zygadlo , Yossef Osman , Bjorn Helgaas , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)), "H. Peter Anvin" , Alex Deucher , =?UTF-8?q?Christian=20K=C3=B6nig?= , David Airlie , Simona Vetter , Harry Wentland , Leo Li , Rodrigo Siqueira , Kenneth Feng , Hans de Goede , =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= , Andre Eikmeyer , linux-pci@vger.kernel.org (open list:PCI SUBSYSTEM), linux-kernel@vger.kernel.org (open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)), amd-gfx@lists.freedesktop.org (open list:RADEON and AMDGPU DRM DRIVERS), dri-devel@lists.freedesktop.org (open list:DRM DRIVERS), platform-driver-x86@vger.kernel.org (open list:X86 PLATFORM DRIVERS) Subject: [PATCH v2 06/12] platform/apple-gmux: Add check to detect FSS Date: Sat, 14 Nov 2026 11:06:30 -0500 Message-ID: <20261114160731.3756-7-atharvatiwarilinuxdev@gmail.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20261114160731.3756-1-atharvatiwarilinuxdev@gmail.com> References: <20261114160731.3756-1-atharvatiwarilinuxdev@gmail.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On MMIO macs, there is feature called FSS, we assume its a display syncing technology between internal links (for example 5K iMacs). We detect it and then warn the user about it, if its broken/unavailable. Tested-by: Sebastian Zygadlo Tested-by: Yossef Osman Signed-off-by: Atharva Tiwari --- drivers/platform/x86/apple-gmux.c | 2 ++ include/linux/apple-gmux.h | 1 + 2 files changed, 3 insertions(+) diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c index c4a953b5b..a1b7a4709 100644 --- a/drivers/platform/x86/apple-gmux.c +++ b/drivers/platform/x86/apple-gmux.c @@ -1196,6 +1196,8 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id) gmux_enable_interrupts(gmux_data, 1); gmux_read_switch_state(gmux_data); + if (type == APPLE_GMUX_TYPE_MMIO && gmux_read8(gmux_data, GMUX_PORT_FSS) & 1) + pr_warn("FSS Failure, display tearing expected\n"); /* * Retina MacBook Pros cannot switch the panel's AUX separately * and need eDP pre-calibration. They are distinguishable from diff --git a/include/linux/apple-gmux.h b/include/linux/apple-gmux.h index 206d97ffd..a4fa84500 100644 --- a/include/linux/apple-gmux.h +++ b/include/linux/apple-gmux.h @@ -22,6 +22,7 @@ #define GMUX_PORT_VERSION_RELEASE 0x06 #define GMUX_PORT_SWITCH_DISPLAY 0x10 #define GMUX_PORT_SWITCH_GET_DISPLAY 0x11 +#define GMUX_PORT_FSS 0x12 #define GMUX_PORT_INTERRUPT_ENABLE 0x14 #define GMUX_PORT_INTERRUPT_STATUS 0x16 #define GMUX_PORT_SWITCH_DDC 0x28 -- 2.55.0