From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sebastian Andrzej Siewior Subject: Re: [PATCH] dma: omap-dma: add support for pause of non-cyclic transfers Date: Fri, 07 Aug 2015 18:20:44 +0200 Message-ID: <55C4DADC.9070004@linutronix.de> References: <1438936917-7254-1-git-send-email-bigeasy@linutronix.de> <55C47DE1.9020902@ti.com> <55C48A1E.3070007@linutronix.de> <20150807132241.GN7576@n2100.arm.linux.org.uk> <55C4B5AE.10309@linutronix.de> <20150807135727.GP7576@n2100.arm.linux.org.uk> <55C4CA00.3060206@hurleysoftware.com> <20150807152939.GQ7576@n2100.arm.linux.org.uk> <55C4D7AF.8060305@hurleysoftware.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <55C4D7AF.8060305@hurleysoftware.com> Sender: linux-kernel-owner@vger.kernel.org To: Peter Hurley , Russell King - ARM Linux Cc: Peter Ujfalusi , Vinod Koul , Dan Williams , dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, nsekhar@ti.com, linux-omap@vger.kernel.org, linux-serial@vger.kernel.org, john.ogness@linutronix.de, Greg KH List-Id: linux-omap@vger.kernel.org On 08/07/2015 06:07 PM, Peter Hurley wrote: >> If we look at what 8250-dma.c is doing: >> >> if (dma->rx_running) { >> dmaengine_pause(dma->rxchan); >> >> It's 8250-dma.c which is silently _ignoring_ the return code, failing >> to check that the operation it requested worked. Maybe this should be >> WARN_ON(dmaengine_pause(dma->rxchan)) or at least it should print a >> message? > > Thanks for the suggestion; I'll hold on to that and push it after we add > the 8250 omap dma pause in mainline. I have a patch ready with WARN_ON_ONCE() for 8250-omap and 8250-dma. This warning would trigger on am335x/edma until v4.2-rc1 and omap-dma based version is open. I could post it if you want me to. Besides that those two, there are four other drivers ignoring the return code dmaengine_pause(). Sebastian