From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=74.125.82.180 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794672581; b=mc00ZlDhVb4CGZCtlNvr3ptIkXBeXYDziN78uZ+XdN5UY5LEuveJnspOxSCSq50ujQcp Ban1RnUEz4SYM9YsYFloCwTynn5t8ogea0RnseLOd9zvsd31p8dy4AIicVpaCJCfg5Ya8 ecmiQ3oLyz/bFYyWbJYg11VPLyvsyZQIjBA8joK5oOUMfsBr3Whixj/o3w0+V07derBer XQBm3YXfb1UHdERK30fcAbz6D7i7ivOqe3cQgH7ffVbsIv+k5uQFSgGyYfMPA34CevE0O eblzbatyhIHlp4EAlwq8M35eiFFsltiWTGW3R/Q5kkdO/rl7wB5SSXpXnwVN3qA7JkQ== 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=5FEzlGKTObHlXvZWaTzqobHosDk9z1OunCu70RFokAchOW1DPjMueGt9Qu8tet65QF4r omWLx4fkTSvo/uTgGBVkihZvAJNwjhPAMBlb2b0HmHVvUEPGJIfPyeJm1iQEYgBli4hvs EDeEwYgekB1cCwc09eex0Ucrc7uck7h7E0qYZYvNzckY/nO+SxLvVxKFGXgFX5r+tKzH7 eYOjT6XxLuYUJivC+cY7ak/58L5JxgpO+bqkRJj9Ee/Atyn3miYq8pGEYBcMvUry+vGZa +u10igaR0MbKcAy7erGb0wc9gRktejFkhNBbuj5NmRTYR3yBxsgJ4Zbx9xQ5KA/FlrA== 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=74.125.82.180 Received: from mail-dy1-f180.google.com (mail-dy1-f180.google.com [74.125.82.180]) (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 7C0FA606A329 for ; Sat, 14 Nov 2026 16:09:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 7C0FA606A329 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-f180.google.com with SMTP id 5a478bee46e88-37986eb6fa2so1680932eec.0 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=0iTLCpvA3QrAHNchziVoetHxnU/FvTqpWKxiOOkeg0V32/iJpi6ZPxLndJ08vmIn35 ysIvLcvtWFiOg1N4h6u7mTT7FS26VGL9h6qvc+3RoWCMxHAcE1RxUrojoEf9cCDvqrxz NY2BcYeRglIpYDNa3xGWytmvXlCSBYh5wRj/U2uKETZIaMkWc9FEXDadYfp6SRxVop28 oRhTYLl5CXqdHEq0y18UL53KtMSzT7zH754u+K+C66gTRDw7yMN9N7Rm1x2k1UkG+KdM 5CJN7/YHp0lBYW49iP5+uoEU3/YrjQmY6PYUbtPV4lRJAQ+Oq36rr1RcMlLwjJsWetYb UuMg== X-Forwarded-Encrypted: i=1; AL+hErHsY2hdlqs+BzyYh17cODgBjRin5FD9c5uKP9Qv9nmOMikt1cD/vot0o6qkmywN2+8emSODvVy4jK4=@vger.kernel.org X-Gm-Message-State: APuU4Z9OPUCWjud53VdcnnvUsZztN1FVAV2fRUDvmkzZZcB3VCYCNWHO lO0KymWe4SCXrMaTpaOCRGpTtxchtUfrcJuI+OZAF1RUAvR+R9EE4rw= X-Gm-Gg: AYBFou1BELG7+rKz6tAgUVxTjKMLLbH2htgDzkLw7SvOp9nEis33nwTbua0bEJCDVeW eURy+/sdW1nzcG2QdYV7QbVypghGvlFQU9IvOrMVnD2Y1zOOxOXguTTzUQRxTFLnIMoNwtpdv1Q Bc4GUd4pwfokCYRFogMhBi03pMZSp3p4TNPkpRt4JmpnskO6+btW8RaaM43N3U+gX9hfOo51PvD Cfhdl9Q2vjtAUR69IDFeFbiYnkYyQqmxXWfe4shh5yVYDd8bFvXAAdRo+6tpeKQYdDj9jPTs7fD QMPbTHnwZhS2fHpYDt6Y7QWI8xd0iaCauTV2ePGA6kn0+URp5H93Ma6mE425ARx/BoOxBVtwoAP PbLhnwDZmA25Dma2WksaUZTyWCllGI7EImqr8jy351u4PpYrDCLfr4p4/JEybTlVr4M9JgzWDYH PXrva9ipGLS9Z/lflyjGMX7F6vrJmxcnMc3Yfe1ufxN6I+epi39mAvw1VbaXBTVB60L60BnmApo 0VhPmHkamdvwJ1X470YDaTnFIppMHXybPs5NVCv+92hwQozeU8ER88mAQlLJyZvz53sV9qeXxjh wA9p3BYrm+qXo7XiWb514lGrklS2KWrqxHrnnyi17/ZWFeQY8XXqvga6Z2IXFFoP0gE= 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-pci@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