From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760585AbbLCPqR (ORCPT ); Thu, 3 Dec 2015 10:46:17 -0500 Received: from mout.kundenserver.de ([212.227.126.131]:52415 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756877AbbLCPqP (ORCPT ); Thu, 3 Dec 2015 10:46:15 -0500 From: Arnd Bergmann To: Peter Ujfalusi Cc: vinod.koul@intel.com, andy.shevchenko@gmail.com, linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, nsekhar@ti.com, tony@atomide.com Subject: Re: [PATCH 3/4] dmaengine: core: Introduce new, universal API to request a channel Date: Thu, 03 Dec 2015 16:45:38 +0100 Message-ID: <4696298.Uj40YldTVN@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: <566062E7.2020705@ti.com> References: <1449153192-9082-1-git-send-email-peter.ujfalusi@ti.com> <6922343.04ZpTXZq7O@wuerfel> <566062E7.2020705@ti.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:/wThiSpi9vHRnfLCEr9OlQXe9ZCNybWrxt8x3p5XcNVjqs80m1h 36Ca/LpHm1dc4l/tOrrx9qrOOJYa9upV2MPRMoRXtqRuci285NAzNxG1OZbGyw5xdKHMiMn JRS5ho6QjlrK5SU863fgwkhCMYeMe8Gf9LIWS/M6aIW4akjZeY2rWoZdMliZGtQbwNQxUUf O9tkAvKeea4DNPui06tBg== X-UI-Out-Filterresults: notjunk:1;V01:K0:P7eXPHeFvus=:87Iei3IBm5EtVVluEJtCyn i+0pTXKeOEDXVmT7xkv47st6ujdMdfv4Lu9izE7XX5p/L6h03jh5rnA1ULNgdNpFl8TLRIvc6 PiMwK0t91LeLrVt3JUDk/G6TdJBN8VY7OhWXEx6tGHGvVKlSikMOWLwmyhmQjO96wuoLGAM7n NK7CGa6s3S3M0EyjIsecvbFStFuU1cTtzInFLd56IgiAWWZTCUlIyXAuYEjDzctepxKLNbPYz WFMgEXwAOAys/ssfCA4zWhHa1P7DlVcypR/y7Il63qZYjxEhex0r95IcTIDWb4yL2e7hs3GeK vBNmtIOhHs5UPn7c7ueuMLwSBl78gDEPrjXkQEn69Hz9N3D0AEYttR4Mt+LzQ7WXOWgbLqE8S zYWH9UGyIJinCnltG+eI3BVML4iY3FxSnLv1TthT3CbVosD7cjuGW6Y+28zn0oNj6TxWmteWw WkNNXOx3ggrgsMlHZPcHdsQoYQpM1nDTOE46LM8CcFlZ9qAqIyoKVuany4nVqT30x9kXQW9T3 QuZ9ZMruOcmJuJ8RUOlW2OEM0o5osxQjCzIdGDHj5/WiH6i2JLHi4+0/IabLpSoIypMORbZK0 oiRVfB/vznR5FwPhXvpqUJSoV+9OOozGeYog1rFs+HlNM1q5KEIuIBJVdRFXbq7nH7RgTEVOP imSOSfHWEGfkrGdbZO2Wne8R+V3rVQwAMlXHULdU0vJS+Yh6DTSwJyAxABBRa9lcZP9AY82og 0iVjbzn+x1Hg2k3H Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 03 December 2015 17:42:31 Peter Ujfalusi wrote: > > > >> + if (chan) { > >> + /* Valid channel found */ > >> + if (!IS_ERR(chan) || PTR_ERR(chan) == -EPROBE_DEFER) > >> + return chan; > >> + > >> + pr_warn("%s: %s DMA request failed, falling back to legacy\n", > >> + __func__, dev->of_node ? "OF" : "ACPI"); > >> + } > > > > Maybe print the error code as well? > > Or remove the print altogether? > In a healthy system we will either get the channel or the EPROBE_DEFER, in > case of the platforms where the DT lookup does not work we expect errors and > it is 'normal'. > I think if we fail via DT/ACPI and we fail with legacy also then the client > driver will say something about it anyways, or deal with it as it see fits. > Right, that works too. It took me a while to figure out that we only get there on systems that have ACPI or DT enabled for a particular device, but where the normal method failed, rather than also systems with traditional board files. Without the pr_warn, I would not have needed to think about this ;-) Arnd