From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 ECB1038A729; Fri, 3 Jul 2026 07:10:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783062622; cv=none; b=Bm2LfmlkB/eNFui4OQyZVcUvf/9N5EG98Qxh2wraDsNwe4IZ9vJf9qRhm4t+4GLoi7AggYYB9oIrQL4eN70IGt2mjE/agqzEnd8SGjorLzRrX7q2Hf6fEAMJkvsklbVn52iEF1Xa+W+Xvo/XAygUXc8BnZh93cH4NS9KmS9RN1g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783062622; c=relaxed/simple; bh=Au7XCecHtF2tigo2BWCNwOZTr1iYKRba1SqJsXZfwIY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=gmXDgjzD1hmYHLR9XRaB2Sjw1dlWWzp7nyq1ZmMGu34ex/Ymy17BLmw/K6pJkYCiaNiLgqqBM1xesWyesmFKll/ZHAxOTTxEz56bKhVar1HuAz3akzVnHwoveJow6nHroq27996v8YpVzMgq3INLgjmu5/VbM8L4LnFH7Wi5MyM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=T5p9sIR/; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="T5p9sIR/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CED571F000E9; Fri, 3 Jul 2026 07:10:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783062619; bh=5EHukF5H/z9l9uC2WxZRVzgW9mK1DchOxCTKztHSowk=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=T5p9sIR/c3iKErjZCsuxu797uuaK++oKaepi2ujfJjvVEfav6h5ZRF8W/pqp46ZIN CSVbwulKUChwFEoTcKcogGloLiN0iOyozBS6wBJ4oJRMXyQsM0mZGjgWHybnAS6cF4 8tKS6VNyxGNfCtfOd5PEKtOOE1Hefv0Vb7+FI8wsYKJJ8Y/8QXz9bmdwhUuTbAq6Mx VzJGQc0SxfYZRT1E3CvXpgLR5p/hG0MVEcjYHDlW8RHCE/eCsh+KbPiPZot1biRH6S 0I2oNFToeebbrQoKt+0O6XDWa9Pak+hDp9hidHEDQzaz3KQ+hNGX4iEKhKo+96Kd0R KH6D41Ge2Wmtg== Message-ID: <7ecf28a5-1c69-41b9-a6ed-0bf14f62b9fa@kernel.org> Date: Fri, 3 Jul 2026 09:10:10 +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 2/4] dt-bindings: display: tegra: Add channel/syncpoint range properties To: Mikko Perttunen Cc: Thierry Reding , Jonathan Hunter , David Airlie , Simona Vetter , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Rob Herring , Krzysztof Kozlowski , Conor Dooley , linux-tegra@vger.kernel.org, dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260622-host1x-nohv-v1-0-65bc682a617f@nvidia.com> <20260626-sceptical-aardvark-from-mars-cedf81@quoll> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit On 29/06/2026 06:02, Mikko Perttunen wrote: > On Friday, June 26, 2026 7:26 PM Krzysztof Kozlowski wrote: >> On Thu, Jun 25, 2026 at 06:26:43PM +0900, Mikko Perttunen wrote: >>> On Thursday, June 25, 2026 5:36 PM Krzysztof Kozlowski wrote: >>>> On Mon, Jun 22, 2026 at 05:22:51PM +0900, Mikko Perttunen wrote: >>>>> Channels and syncpoints available may be limited when other system >>>> >>>> What are channels and syncpoints? >>> >>> Very host1x-specific hardware resources. Somewhat close to GPU channels >>> and semaphores / fences if you're familiar with those. >>> >>>> >>>>> components are using them. Add properties nvidia,channels and >>>>> nvidia,syncpoints to limit the range of usable channels and/or >>>>> syncpoints. >>>> >>>> Why isn't this deducible from the compatible? >>> >>> When Host1x is partitioned, the hypervisor (or other software entity >>> with access to the non-vm host1x register regions) can configure which >>> channels and syncpoints are available to each partition arbitrarily. >> >> So you will have different boards for the same SoC with different >> values? >> > > Yes -- even the same board will have different values depending on the > use case of the system. The hypervisor or bootloader has to update the > properties according to the configuration it has programmed in the > hardware. > > I will update the commit message with clarification. > >>> >>> How that partitioning was done is not discoverable through hardware >>> directly, so we need to pass that information through device tree. >>> >>>> >>>> Also, nvidia,channels is too broad/generic. This is not ADC, right? And >>>> channels is a common term in IIO. And in few other cases. >>> >>> It's not ADC. Yes, it's a common term in a lot of contexts. I can call >>> it nvidia,host1x-channels if you prefer but that seems a bit redundant >>> given the context. >> >> host1x is indeed poor, but maybe there is some way to be a bit more >> descriptive? message-channels? > > I would prefer to keep these as is -- anyone working with host1x will > know what 'channels' and 'syncpoints' mean, and changing the name could > cause confusion since the name would not match other code or > documentation discussing these. > > I can update the binding documentation with some more explanation about > what these properties mean. Property has only one meaning in DT schema, so basically you are now fixing nvidia,channels to uint32-array for all possible use cases and nvidia devices. Well, you have been warned. Best regards, Krzysztof