From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 20638C7619A for ; Mon, 27 Mar 2023 08:13:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232893AbjC0INl (ORCPT ); Mon, 27 Mar 2023 04:13:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43250 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232970AbjC0IN3 (ORCPT ); Mon, 27 Mar 2023 04:13:29 -0400 Received: from muru.com (muru.com [72.249.23.125]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id F40C449CA; Mon, 27 Mar 2023 01:13:28 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTPS id 4411C8108; Mon, 27 Mar 2023 08:13:28 +0000 (UTC) Date: Mon, 27 Mar 2023 11:13:27 +0300 From: Tony Lindgren To: Andreas Kemnade Cc: bcousson@baylibre.com, robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, aford173@gmail.com, linux-omap@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, "H. Nikolaus Schaller" Subject: Re: [PATCH] ARM: dts: gta04: fix excess dma channel usage Message-ID: <20230327081327.GE7501@atomide.com> References: <20230113211151.2314874-1-andreas@kemnade.info> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230113211151.2314874-1-andreas@kemnade.info> Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org * Andreas Kemnade [230113 23:12]: > From: "H. Nikolaus Schaller" > > OMAP processors support 32 channels but there is no check or > inspect this except booting a device and looking at dmesg reports > of not available channels. > > Recently some more subsystems with DMA (aes1+2) were added filling > the list of dma channels beyond the limit of 32 (even if other > parameters indicate 96 or 128 channels). This leads to random > subsystem failures i(e.g. mcbsp for audio) after boot or boot > messages that DMA can not be initialized. > > Another symptom is that > > /sys/kernel/debug/dmaengine/summary > > has 32 entries and does not show all required channels. > > Fix by disabling unused (on the GTA04 hardware) mcspi1...4. > Each SPI channel allocates 4 DMA channels rapidly filling > the available ones. > > Disabling unused SPI modules on the OMAP3 SoC may also save > some energy (has not been checked). Applying this into omap-for-v6.4/dt based on what we discussed in this thread earlier. Thanks, Tony