Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757826AbYLKQ4y (ORCPT ); Thu, 11 Dec 2008 11:56:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756965AbYLKQ4l (ORCPT ); Thu, 11 Dec 2008 11:56:41 -0500 Received: from mail.gmx.net ([213.165.64.20]:60856 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1756550AbYLKQ4k (ORCPT ); Thu, 11 Dec 2008 11:56:40 -0500 X-Authenticated: #20450766 X-Provags-ID: V01U2FsdGVkX1/00YBFXT/0sT3DI5ATTZGUmk4vvdfyLbV8Bimt+K jV9aJmBYDRq/zz Date: Thu, 11 Dec 2008 17:56:51 +0100 (CET) From: Guennadi Liakhovetski To: Dan Williams cc: Guennadi Liakhovetski , linux-kernel@vger.kernel.org, linux-fbdev-devel@lists.sourceforge.net, adaplas@gmail.com, Sascha Hauer , linux-arm-kernel@lists.arm.linux.org.uk Subject: Re: [PATCH 1/4 v2] dmaengine: add a tx_free method to struct dma_async_tx_descriptor In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Y-GMX-Trusted: 0 X-FuHaFi: 0.59 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1402 Lines: 32 On Thu, 11 Dec 2008, Dan Williams wrote: > On Thu, Dec 11, 2008 at 8:55 AM, Guennadi Liakhovetski > wrote: > > > > Sorry, actually, it's not VIDIOC_DQBUF where we have to free buffer(s), > > it's VIDIOC_STREAMOFF. And in a normal case there are no more completion > > interrupts, no allocation requests, and noone is interested in > > is_tx_complete. Normally you would just get a dma_release_channel after > > that. Or, of course, the application may decide to restart capture, then > > we get requests, completions, etc. again. So, yes, I could do this, it > > just seems a bit unnatural to me. > > Could the application tolerate another call to dma_request_channel > when it restarts? I.e. just call dma_release_channel from the ioctl > to clean everything up and not worry about another free() mechanism? For V4L - yes, I could do this. But is it a good idea to hard-code into a "generic" dma driver (or at least something that pretends to be a generic driver), that descriptors can only ever be freed by releasing the channel?... Thanks Guennadi --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/