Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751612AbbEGUyg (ORCPT ); Thu, 7 May 2015 16:54:36 -0400 Received: from mail-la0-f49.google.com ([209.85.215.49]:36763 "EHLO mail-la0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751169AbbEGUyd (ORCPT ); Thu, 7 May 2015 16:54:33 -0400 MIME-Version: 1.0 In-Reply-To: <20150507202439.GA4717@breakpoint.cc> References: <20150507202439.GA4717@breakpoint.cc> Date: Thu, 7 May 2015 17:54:31 -0300 Message-ID: Subject: Re: [PATCH] serial: imx: Revert "initialized DMA w/o HW flow enabled" From: Fabio Estevam To: Sebastian Andrzej Siewior Cc: Greg Kroah-Hartman , Sebastian Andrzej Siewior , jiwang , Jiri Slaby , "linux-serial@vger.kernel.org" , linux-kernel , anton_bondarenko@mentor.com, Dirk Behme , Nicolae Rosia , Fabio Estevam Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1937 Lines: 42 On Thu, May 7, 2015 at 5:24 PM, Sebastian Andrzej Siewior wrote: > From: Sebastian Andrzej Siewior > > This basically reverts commit 068500e08dc8 ("serial: imx: initialized > DMA w/o HW flow enabled") simply because it does not work as expected > without additional magic which I am not aware of. The DMA mode is only > used for non-console UARTs so the "standard" boot test won't notice this. > > I tested it on various IMX6 (S and Q) boards and the default SDMA firmware > that is included in ROM does work properly. The SDMA interrupt counter does > not stop increment (which means the SDMA does not stop working or the ACK > is working) and I see a lot of 0x00 (sometimes other bytes) which are added > to the tty buffer which are not part of the data transfer. > Jiada claimed that there is a firmware which makes it work but failed to > provide me a link to the firmware. All he said was that it can not be > shipped as part of the kernel due to license issues. I've found a firmware > blob in the FSL-tree but this firmware causes only TTY-overflows an *no* > data is transmitted. > > Currently I see no other way out. > > Fixes: 068500e08dc8 ("serial: imx: initialized DMA w/o HW flow enabled") > Cc: Fabio Estevam > Cc: Jiada Wang > Cc: nicolae.rosia@gmail.com > Signed-off-by: Sebastian Andrzej Siewior Thanks, this fixes Bluetooth operation on a imx6sl-warp running without SDMA firmware. Two suggestions: 1. You should Cc stable as it affects 4.0 also 2. It doesn't apply cleanly against linux-next, so I think Greg will have problems applying it. -- 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/