From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 780491FF5F4; Wed, 5 Feb 2025 19:35:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738784115; cv=none; b=sru7cxYGiu1mKI13untadRXGtUGWv0iQQGEG9QxbHOJqFWavS73tQrdPXCNpKgav1FUmuErKAybffGL6gcN+LX4MZcbNgH9SwJCEQd/tdgFhADvtknYfdBxBF9+kCCo0BszQCHWfBYOZZOpiL5ORl2S9wLyVV4EJ1U67WR1MaIw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738784115; c=relaxed/simple; bh=ShcZHGBdifSRfT1a3wdja/S42QVCg8pR07DE0bj9C2A=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=E7BK/HNBnPQ1Ww7GelOP/gd5srXdCPUMu6k39l+S95WN4fUrBICeO1eFcAQKcTM8pm1+sG/lvr1y5mrnhLxrCaXqvn1EdC22nbVm6RFY4WPjUYeKmujWtYiQY2DR6tpShmu05XtUyWJKYIJ/i82Fw3pk4v6MF8NpcsKQuQH3iVE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kkAVgl1X; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kkAVgl1X" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9B83FC4CED1; Wed, 5 Feb 2025 19:35:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1738784114; bh=ShcZHGBdifSRfT1a3wdja/S42QVCg8pR07DE0bj9C2A=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=kkAVgl1Xjzt1q8t/CAipXH+qrumDPqWOhCqysT2XJzi3Q4mjx7rhEr5vXrre6CZwu UYBobVOwJGrYY9J0ZnXTjbgFC8CEzK141Cb6yitgYkWG61mAwSPZ5M39xC0ZcAm3Du n97+odZ/wJpzq+jCACoBPJM2OueummlRWdb5KPKLNW3hQ0rmqbCPzoht2HTFKlCpza AoxJOn1lPHCf5xHScmmz2J1Vo5x8WknrjEUVj/BPpDvyd9j9E2f//UPP1VYzPUyAjS S6KkzuwSOPqt30Q5H7BVKna7OkfGcqMo2l5qGMQq7Xp1IDt0GBdM9OGjo/0nV0PryN mlMk1g1q1BHKg== Message-ID: <73d4153e-cc03-45ba-ae2e-3b9f4baf7346@kernel.org> Date: Wed, 5 Feb 2025 20:35:09 +0100 Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 1/2] dt-bindings: usb: snps,dwc3: Add property for imod To: Badhri Jagan Sridharan Cc: Thinh.Nguyen@synopsys.com, gregkh@linuxfoundation.org, felipe.balbi@linux.intel.com, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, johnyoun@synopsys.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, jameswei@google.com, stable@kernel.org References: <20250202035100.31235-1-badhri@google.com> <20250202-purring-ambitious-axolotl-4c6ff4@krzk-bin> <80172550-a3d7-4d56-927c-ff63debc79f8@kernel.org> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 05/02/2025 19:19, Badhri Jagan Sridharan wrote: >>>> >>>>> + during device mode operation. A value of 0 disables the interrupt >>>>> + throttling logic and interrupts are generated immediately if event >>>>> + count becomes non-zero. Otherwise, the interrupt is signaled when >>>>> + all of the following conditons are met which are, EVNT_HANDLER_BUSY >>>>> + is 0, event count is non-zero and at least 250ns increments of this >>>>> + value has elapsed since the last time interrupt was de-asserted. >>>> >>>> Why is this property of a board? Why different boards would wait >>>> different amount of time? >>> >>> Interrupt moderation allows batch processing of events reported by the >>> controller. >>> A very low value of snps,device-mode-intrpt-mod-interval-ns implies >>> that the controller will interrupt more often to make the host >>> processor process a smaller set of events Vs a larger value will wake >>> up the host processor at longer intervals to process events (likely >>> more). So depending what the board is designed for this can be tuned >>> to achieve the needed outcome. >> >> I do not see dependency on the board. Host has the same CPU always, so >> it processes with the same speed. > > By "host processor", I am referring to the CPU which is scheduling > the TRBs and responding to the events reported by the Synopsys DWC3 > controller. In a nutshell, the CPU which is driving the Synopsys DWC3 > controller. The Synopsys DWC3 controller could be paired with any CPU > configuration and therefore is "Host has the same CPU always" a fair > assumption to be made ? Not really, this is part of a SoC, so DWC3 controller is always here fixed per given setup with given CPU. You claim that this is independent of SoC, but so far arguments do not support that statement. This is related to given SoC, so no need for this property and you can deduce everything from SoC. You push this as a property because you (or vendor) do not want to upstream your SoC. That's common pattern, seen here many times. BTW, good counter argument would be to show me patches for upstream DTS users of this. Actually that would be very easy way to finish discussion... but there are no patches, right? Why? Because it is not upstream and it is done for downstream solution. Sorry, no. Develop code how upstream develops, not downstream. Best regards, Krzysztof