Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754234AbaGHUE4 (ORCPT ); Tue, 8 Jul 2014 16:04:56 -0400 Received: from smtprelay.synopsys.com ([198.182.44.111]:47243 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754138AbaGHUEy convert rfc822-to-8bit (ORCPT ); Tue, 8 Jul 2014 16:04:54 -0400 From: Paul Zimmerman To: Bartlomiej Zolnierkiewicz , "Dinh Nguyen (dinguyen@altera.com)" CC: Felipe Balbi , Greg Kroah-Hartman , Ben Dooks , "Robert Baldyga" , Kyungmin Park , "linux-usb@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: RE: [PATCH] usb: dwc2: remove incomplete DMA support from gadget code Thread-Topic: [PATCH] usb: dwc2: remove incomplete DMA support from gadget code Thread-Index: AQHPmrycS0FNgw5mhES6/ILZKpsVs5uWl/pw Date: Tue, 8 Jul 2014 20:04:47 +0000 Message-ID: References: <2181126.aCTfeXMESu@amdc1032> In-Reply-To: <2181126.aCTfeXMESu@amdc1032> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.9.64.241] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > From: Bartlomiej Zolnierkiewicz [mailto:b.zolnierkie@samsung.com] > Sent: Tuesday, July 08, 2014 7:55 AM > > The commit 5b7d70c6dbf2 ("USB: Gadget driver for Samsung HS/OtG > block") which added this driver also introduced the inactive DMA > support (due to hardware limitations of DMA buffers alignment). > It has been a dead code for over 5 years and should be removed. > > We don't keep the unused/untested features in the kernel. Such > code has a real maintainance cost (all other changes have to take > dead code into account), i.e. https://lkml.org/lkml/2014/5/6/461. > Also all the removed dead code is still accessible in the kernel > git repository and can be easily brought back if/when needed. > > There should be no functional changes caused by this patch. > > Signed-off-by: Bartlomiej Zolnierkiewicz > Acked-by: Kyungmin Park Hmm. I'd rather not apply this for the time being. Dinh Nguyen is working on a patch to combine the two dwc2 drivers into a dual-role driver. I suspect his platform will be able to use DMA. Also, once that is done, I plan to enable device-mode support for the Synopsys development platform, which also supports DMA. If none of this happens over the next couple of months, we can reconsider applying this patch. After all, the code has been there for 5 years, a couple more months won't hurt. Sound OK? -- Paul -- 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/