From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B966E195B14; Mon, 23 Sep 2024 12:25:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.251.105.195 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727094313; cv=none; b=erdPkMrWxTzSNyp+gAhospmI4QhrqNapgKlAiPYGF5SmOgL2Uqt1hkpCw8g18fHzFDGvt7I3whRRuyBY47TFgQgqQ9rNoE6vVN3YnNXPO55KjjiYdX18WT3+YVvxX/R31GCKm2FBPEoiIgtEW1UVbiHPSRwzw37+viTPULPzcUc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727094313; c=relaxed/simple; bh=oVnappwI2asg1Mmf+oMcKojkg9+Z0J7WmOxhJWSM3kc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=UsGAD2KnKSWsSxZ4WrEQ8pfNVupEAVxhnafJ4mLJ2o45LkxrIZvppKb8xpJoA78F2LeKJReNcc3BomtoLFTlnHp7UDkyL5UQeSNTkPBNngIB1N/6KNJXljevmmZx4MpewxN5hWx1cN7h1IoFPA63tlvQP+3tANFoetLVxjP1vL4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b=Tj/L4nvR; arc=none smtp.client-ip=148.251.105.195 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b="Tj/L4nvR" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1727094309; bh=oVnappwI2asg1Mmf+oMcKojkg9+Z0J7WmOxhJWSM3kc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Tj/L4nvRSp5Oa5oywuog3blCYKnRcOhvwJvam8UXfvTh1zG0pASOMhRoDtDkiGfqO pB6vekai1WFqwSw3bww3yvYXWjavV6cR/8bTXfAUex/Zuvw2K6uvq3HAwegPKO3M9i DNjlEJLMjzrbxxnmHjsk1zEV8/T2cuyQbAombyyddafGJMMIcEjsPBlC6eUHTvdDLn TfP1T2k5CDNte7JF9YXwQ4e7QfHt0kXR7FY8B95H8Wi3xWZ9IInMzsEUPSyJG6P+GI y+fxOvLEU486ptT4KFrQlH3ZZsyZvZ/wPmXbQrMWncY3tYS1XeBB53x+mItSG24WP2 1Q7KulaV9+G7A== Received: from [192.168.1.100] (2-237-20-237.ip236.fastwebnet.it [2.237.20.237]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: kholk11) by bali.collaboradmins.com (Postfix) with ESMTPSA id 7E36817E121B; Mon, 23 Sep 2024 14:25:09 +0200 (CEST) Message-ID: <228c9508-76c3-4772-bf0a-56e85a47af78@collabora.com> Date: Mon, 23 Sep 2024 14:25:09 +0200 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 5/5] arm64: dts: mediatek: mt8390-genio-700-evk: Enable Mali GPU To: Pablo Sun , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Matthias Brugger , Michael Turquette , Stephen Boyd , Srinivas Kandagatla Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-clk@vger.kernel.org References: <20240920134111.19744-1-pablo.sun@mediatek.com> <20240920134111.19744-6-pablo.sun@mediatek.com> From: AngeloGioacchino Del Regno Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Il 23/09/24 12:14, Pablo Sun ha scritto: > Hi Angelo, > > On 9/23/24 16:45, AngeloGioacchino Del Regno wrote: > [snipped] >> >> Is there any real difference between MT8390 and MT8188 in terms of the GPU OPPs? >> >> I see that on MT8188, frequencies up to 880MHz want a DVDD_SRAM_GPU of 0.750V, >> then 0.775/0.762/0.750 (bin1-4/5/6) on 915MHz, and 0.800/0.775/0.750 (bin1-4/5/6) >> on 950MHz. >> >> Those never call for 0.850V...! So is MT8188 (Chromebooks) wrong, or is MT8390 >> different in that? > > To the best of my knowledge, MT8390 and MT8188 has identical GPU > subsystem. Thus, the OPP table should have no difference. > > To be specific, I list the link to the OPP table of Genio 700 EVK > (MT8390) in reference in [1]. It should match the setting in Chromebook > kernel branches. > > The "typical" voltage in the datasheet is the voltage that would work > for all frequency settings. As long as it is smaller than the maximum > operating voltage, setting voltages higher than the ones specified in > the OPP table does not damage the hardware. > > But this 0.85V setting is indeed not optimal. We should follow the > voltages described in the OPP table, if we want power savings. > > I also considered model the regulator setting with 'regulator-coupled-with' and > 'regulator-coupled-max-spread', but I am not entirely sure how to describe the > relation that "DVDD_GPU_SRAM should follow DVDD_GPU > if and only if DVDD_GPU is higher than 0.75V" - should I simply > set min-voltage to 0.75V and set 'regulator-coupled-with' ? > VSRAM_GPU regulator: regulator-min-microvolt = <750000>; regulator-max-microvolt = <800000>; regulator-coupled-with = <&(vgpu regulator)>; regulator-coupled-max-spread = <1000>; VGPU regulator: regulator-min-microvolt = <400000>; regulator-max-microvolt = <800000>; regulator-coupled-with = <&(vsram_gpu regulator)>; regulator-coupled-max-spread = <1000>; Cheers, Angelo > [1]: > https://gitlab.com/mediatek/aiot/rity/meta-mediatek-bsp/-/blob/kirkstone/recipes-kernel/dtbo/mt8390/gpu-mali.dts > > Many thanks, > Pablo >