From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Hunter Subject: Re: [PATCH v3 09/13] dmaengine: tegra-apb: Remove runtime PM usage Date: Tue, 7 Jan 2020 15:13:52 +0000 Message-ID: References: <20200106011708.7463-1-digetx@gmail.com> <20200106011708.7463-10-digetx@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20200106011708.7463-10-digetx@gmail.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Dmitry Osipenko , Laxman Dewangan , Vinod Koul , Dan Williams , Thierry Reding , =?UTF-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= Cc: dmaengine@vger.kernel.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-tegra@vger.kernel.org On 06/01/2020 01:17, Dmitry Osipenko wrote: > There is no benefit from runtime PM usage for the APB DMA driver because > it enables clock at the time of channel's allocation and thus clock stays > enabled all the time in practice, secondly there is benefit from manually > disabled clock because hardware auto-gates it during idle by itself. This assumes that the channel is allocated during a driver initialisation. That may not always be the case. I believe audio is one case where channels are requested at the start of audio playback. Jon -- nvpublic