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 X-Spam-Level: X-Spam-Status: No, score=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0BB4AC31E5B for ; Tue, 18 Jun 2019 15:12:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D65FF21479 for ; Tue, 18 Jun 2019 15:12:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="RzFJ/8d2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729249AbfFRPMI (ORCPT ); Tue, 18 Jun 2019 11:12:08 -0400 Received: from mail-wr1-f67.google.com ([209.85.221.67]:37457 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729242AbfFRPME (ORCPT ); Tue, 18 Jun 2019 11:12:04 -0400 Received: by mail-wr1-f67.google.com with SMTP id v14so14413018wrr.4 for ; Tue, 18 Jun 2019 08:12:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=XMfa9NJpDXh8dDL9yFLkdc/RmjSvoaHVSjRiYPgy7AU=; b=RzFJ/8d2DQVpdpSN66TgWH5FYsc9Os+fcsszwdEdRiHoXMgA1PIV3bLurXKkC7Yfm2 WouFAm13XKYXcw2na3YdFMwyVTomRiE8GcJt7T0UkpCALOrQqSInLzUwFkKfsM2JiAKW axUHeuXw1lVc5yE9i0Nno/wdZI8oyrbEgvtmwDzTRYtZcIp30ff4W0yvUt2j7xoA/gTZ wyC+bN6bQhAd750oPFey+eCSuBBvM3yTCzeAeBlUC83k4E7dzSdV5lcDYAFUBwa1CSOt KlTXHV8Lm/JLy7emfb3OUwFyo8Y3WlHJhQTy+jrci8gAf78nCdsOuN2ZG2JIv2gv7chT pr/g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=XMfa9NJpDXh8dDL9yFLkdc/RmjSvoaHVSjRiYPgy7AU=; b=nGITAt+tJ8XsE2bd1a3bTCs01JS5rk+ecm0gpYMATu7CKQDOAX98vlRDI3+Bj6HkIo PnKVL6Xaeyj3afCnSd4Zt/WGAnAAmY0orCu2uIwN+ZvKEms8+coTf9QvdeC0w0sFz7/p Og9h6rzlcf+iNv99qSKv7bhlT5ydwe6nkD6JSImMk8AuiX0RNQoEWGou3YIoS6BH5q8j aPnXlozOTb+XLWYgDWfJTRRX2XFPRD0t4QVeoiOIy5wXGYlewZeGUmd1qg+GSAYoSN+G Qal9Ow3w1cDBEn+/OdGRgWgkfMY0d48lHGjEXqpuU54442f2FEV0hEBvQxscTdbLAdMJ EYGQ== X-Gm-Message-State: APjAAAXJ2y50gPwOnI2wKqPPkHR5py5QohQhowQgUTDj+8MnB4/occ3H 8cqoB4fmEML4faT8XpRqdqf9Cg+jGr4B2g== X-Google-Smtp-Source: APXvYqyrqTtNMWynSOgiXHoVZjhnncDqEEw1XV2KrhXPMaVDno3t7MXb5Vtc1ZRd/MUwl+UmMXGINA== X-Received: by 2002:a5d:488b:: with SMTP id g11mr5139572wrq.72.1560870722429; Tue, 18 Jun 2019 08:12:02 -0700 (PDT) Received: from [192.168.86.34] (cpc89974-aztw32-2-0-cust43.18-1.cable.virginm.net. [86.30.250.44]) by smtp.googlemail.com with ESMTPSA id x83sm2964625wmb.42.2019.06.18.08.12.01 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 18 Jun 2019 08:12:01 -0700 (PDT) Subject: Re: [PATCH] dmaengine: qcom-bam: fix circular buffer handling To: Sricharan R , vkoul@kernel.org Cc: dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org References: <20190614142012.31384-1-srinivas.kandagatla@linaro.org> <2d370a33-fa16-45ca-cf82-9d775349f806@codeaurora.org> From: Srinivas Kandagatla Message-ID: <544851f6-58b8-2506-01ce-5c4d1f93fb3c@linaro.org> Date: Tue, 18 Jun 2019 16:12:01 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <2d370a33-fa16-45ca-cf82-9d775349f806@codeaurora.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On 18/06/2019 15:56, Sricharan R wrote: > So MAX_DESCRIPTORS is used in driver for masking head/tail pointers. > That's why we have to pass MAX_DESCRIPTORS + 1 so that it works > when the Macros does a size - 1 Isn't that incorrect to do that, pretending to have more descriptors than we actually have? --srini