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=-5.5 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 9103BC433E9 for ; Wed, 10 Feb 2021 15:35:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4675464E85 for ; Wed, 10 Feb 2021 15:35:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232089AbhBJPfH (ORCPT ); Wed, 10 Feb 2021 10:35:07 -0500 Received: from mail29.static.mailgun.info ([104.130.122.29]:30532 "EHLO mail29.static.mailgun.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230171AbhBJPef (ORCPT ); Wed, 10 Feb 2021 10:34:35 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1612971252; h=Content-Transfer-Encoding: Content-Type: In-Reply-To: MIME-Version: Date: Message-ID: From: References: Cc: To: Subject: Sender; bh=gYDWp2DBmUwEH+WiGYQHXHVYycuwNIh7HiMRKaFXJXs=; b=X/xh3EHLEDx5MPvNd8gIod5iaL+82R4+UF5OI0oOact/GpK5MIkrqJWDPDchkuJ/FpoNitKD zmNFM1dWjQWOYnX0rx/vKSnliTjeLFRueE3NoeGfoDJIjJWeZOryq5t8tD9pAMc3K+oWkRkC zIr7ziPLDxw3ii1n62vZc9Sxi2k= X-Mailgun-Sending-Ip: 104.130.122.29 X-Mailgun-Sid: WyI0MWYwYSIsICJsaW51eC1rZXJuZWxAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n04.prod.us-west-2.postgun.com with SMTP id 6023fcd634db06ef79374eb6 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Wed, 10 Feb 2021 15:33:42 GMT Sender: mojha=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 8A403C433CA; Wed, 10 Feb 2021 15:33:42 +0000 (UTC) Received: from [192.168.29.2] (unknown [49.37.87.15]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: mojha) by smtp.codeaurora.org (Postfix) with ESMTPSA id 7273EC433C6; Wed, 10 Feb 2021 15:33:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 7273EC433C6 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=mojha@codeaurora.org Subject: Re: Pstore : Query on using ramoops driver for DDR To: "Luck, Tony" , lkml Cc: "keescook@chromium.org" , Anton Vorontsov , "ccross@android.com" References: From: Mukesh Ojha Message-ID: <9a653cf1-ab22-15c1-d021-a7cfe2b78276@codeaurora.org> Date: Wed, 10 Feb 2021 21:03:20 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/10/2021 2:32 AM, Luck, Tony wrote: >> Can we use existing backend pstore ram driver (fs/pstore/ram.c) for DDR >> instead of SRAM ? > The expectation for pstore is that the system will go through a reset when it > crashes. Most systems do not preserve DDR contents across reset. > > to support DDR, If we have a mechanism to copy stored data from DDR to > external device after the crash. >> Was the current driver written only to support persistant RAM like SRAM >> or it can accept further change > Linux is in a constant state of change :-) > > See above about DDR contents. But if you have a platform that does preserve > DDR contents until your "mechanism" can copy the pstore buffer, then post > a patch. Thanks for the reply I have posted the patch. https://lore.kernel.org/patchwork/patch/1378949/ -Mukesh > > -Tony