From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomasz Figa Subject: Re: [PATCH 10/18] spi: s3c64xx: Do not require legacy DMA API in case of S3C64XX Date: Tue, 13 Aug 2013 22:20:19 +0200 Message-ID: <1686992.nQEd3xdoHn@flatron> References: <1376243970-6489-1-git-send-email-tomasz.figa@gmail.com> <20130813185547.GD6427@sirena.org.uk> <20130813201816.GG6427@sirena.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-bk0-f41.google.com (mail-bk0-f41.google.com [209.85.214.41]) by alsa0.perex.cz (Postfix) with ESMTP id B5B7C2652C4 for ; Tue, 13 Aug 2013 22:20:22 +0200 (CEST) Received: by mail-bk0-f41.google.com with SMTP id na10so2501628bkb.14 for ; Tue, 13 Aug 2013 13:20:22 -0700 (PDT) In-Reply-To: <20130813201816.GG6427@sirena.org.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: Mark Brown Cc: alsa-devel@alsa-project.org, linux-samsung-soc@vger.kernel.org, Mike Turquette , Liam Girdwood , Sangbeom Kim , Vinod Koul , Linus Walleij , Padmavathi Venna , linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org, Takashi Iwai , Kukjin Kim , Dan Williams , Russell King , linux-arm-kernel@lists.infradead.org List-Id: alsa-devel@alsa-project.org On Tuesday 13 of August 2013 21:18:16 Mark Brown wrote: > On Tue, Aug 13, 2013 at 07:55:47PM +0100, Mark Brown wrote: > > I'm still debugging what's going on here - the basic refcounting all > > looks OK in the SPI driver, I can see it requesting and releasing with > > the refcounts all going back to zero in the DMA driver as expected but > > when we come back to the device later on dmaengine is deciding the > > device is unavailable quite early on in the process. > > The failure is happening because this check is failing: > > /* devices with multiple channels need special handling as we need to > * ensure that all channels are either private or public. > */ > if (dev->chancnt > 1 && !dma_has_cap(DMA_PRIVATE, dev->cap_mask)) > list_for_each_entry(chan, &dev->channels, device_node) { > /* some channels are already publicly allocated */ > if (chan->client_count) { > > which is happening because dma1chan0 (which is on the same DMA > controller as the SPI controller) and in fact every other DMA channel > had references grabbed by the network stack dmaengine helpers which I'd > enabled in config. The fact that they do that is unhelpful, it renders > the API mostly useless, but is nothing to do with this series. > > Having tweaked the config everything appears to work so: > > Tested-by: Mark Brown > > though the whole thing with the filter function is as I say a bit fun > from a code review point of view. I believe you just found another brokenness of current DMA channel matching. Thanks for testing. Best regards, Tomasz