From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755389AbbKCQHm (ORCPT ); Tue, 3 Nov 2015 11:07:42 -0500 Received: from mga02.intel.com ([134.134.136.20]:63160 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755213AbbKCQHk (ORCPT ); Tue, 3 Nov 2015 11:07:40 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,239,1444719600"; d="scan'208";a="677500403" Date: Tue, 3 Nov 2015 21:40:13 +0530 From: Vinod Koul To: Timur Tabi Cc: Sinan Kaya , dmaengine@vger.kernel.org, cov@codeaurora.org, jcm@redhat.com, Dan Williams , linux-kernel@vger.kernel.org Subject: Re: [PATCH V2 2/3] dmaselftest: add memcpy selftest support functions Message-ID: <20151103161013.GE12910@localhost> References: <1446444460-21600-1-git-send-email-okaya@codeaurora.org> <1446444460-21600-3-git-send-email-okaya@codeaurora.org> <20151103041528.GS21326@localhost> <5638359D.9080507@codeaurora.org> <5638C55D.50001@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5638C55D.50001@codeaurora.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 03, 2015 at 08:31:57AM -0600, Timur Tabi wrote: > Sinan Kaya wrote: > > > >Almost all DMA engine drivers come with some sort of selftest code > >called from probe. I followed the same design pattern. > > As others have said, it appears that's outdated. > > Is there a real possibility that the hardware could fail the test > without trashing the system? It seems that if the DMA engine is > faulty, it won't "politely" fail. The whole system will crash or > some memory will get corrupted and you won't know it. Failing politely would be right thing to do. If DMA starts sending data to anywhere in system memory due to bug or wrong addresses we can't do anything to prevent that -- ~Vinod