From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 99CA5C433FF for ; Mon, 5 Aug 2019 16:30:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 74CE42086D for ; Mon, 5 Aug 2019 16:30:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729641AbfHEQat (ORCPT ); Mon, 5 Aug 2019 12:30:49 -0400 Received: from mga09.intel.com ([134.134.136.24]:33996 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726620AbfHEQat (ORCPT ); Mon, 5 Aug 2019 12:30:49 -0400 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Aug 2019 09:30:48 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,350,1559545200"; d="scan'208";a="178892890" Received: from buildpc-hp-z230.iind.intel.com (HELO buildpc-HP-Z230) ([10.223.89.34]) by orsmga006.jf.intel.com with ESMTP; 05 Aug 2019 09:30:41 -0700 Date: Mon, 5 Aug 2019 22:02:33 +0530 From: Sanyog Kale To: Pierre-Louis Bossart Cc: alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, tiwai@suse.de, broonie@kernel.org, vkoul@kernel.org, gregkh@linuxfoundation.org, jank@cadence.com, srinivas.kandagatla@linaro.org, slawomir.blauciak@intel.com Subject: Re: [alsa-devel] [RFC PATCH 23/40] soundwire: stream: fix disable sequence Message-ID: <20190805163233.GA24889@buildpc-HP-Z230> References: <20190725234032.21152-1-pierre-louis.bossart@linux.intel.com> <20190725234032.21152-24-pierre-louis.bossart@linux.intel.com> <20190805095620.GD22437@buildpc-HP-Z230> <12799e97-d6e3-5027-a409-0fe37dba86fd@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <12799e97-d6e3-5027-a409-0fe37dba86fd@linux.intel.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 05, 2019 at 10:33:25AM -0500, Pierre-Louis Bossart wrote: > > > On 8/5/19 4:56 AM, Sanyog Kale wrote: > > On Thu, Jul 25, 2019 at 06:40:15PM -0500, Pierre-Louis Bossart wrote: > > > When we disable the stream and then call hw_free, two bank switches > > > will be handled and as a result we re-enable the stream on hw_free. > > > > > > > I didnt quite get why there will be two bank switches as part of disable flow > > which leads to enabling of stream? > > You have two bank switches, one to stop streaming and on in de-prepare. It's > symmetrical with the start sequence, where we do a bank switch to prepare > and another to enable. Got it. I misunderstood it that two bank switches are performed as part of disable_stream. > > Let's assume we are using bank0 when streaming. > > Before the first bank switch, the channel_enable is set to false in the > alternate bank1. When the bank switch happens, bank1 become active and the > streaming stops. But bank0 registers have not been modified so when we do > the second bank switch in de-prepare we make bank0 active, and the ch_enable > bits are still set so streaming will restart... When we stop streaming, we > need to make sure the ch_enable bits are cleared in the two banks. This is clear. Even though the channels remains enabled, i believe there won't be any data pushed on lines as stream will be closed. Regarding mirroring approach, I assume after bank switch we will take snapshot of active bank and program same in inactive bank. > > > > > > > Make sure the stream is disabled on both banks. > > > > > > TODO: we need to completely revisit all this and make sure we have a > > > mirroring mechanism between current and alternate banks. > > > > > > Signed-off-by: Pierre-Louis Bossart > > > --- > > > drivers/soundwire/stream.c | 19 ++++++++++++++++++- > > > 1 file changed, 18 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/soundwire/stream.c b/drivers/soundwire/stream.c > > > index 53f5e790fcd7..75b9ad1fb1a6 100644 > > > --- a/drivers/soundwire/stream.c > > > +++ b/drivers/soundwire/stream.c > > > @@ -1637,7 +1637,24 @@ static int _sdw_disable_stream(struct sdw_stream_runtime *stream) > > > } > > > } > > > - return do_bank_switch(stream); > > > + ret = do_bank_switch(stream); > > > + if (ret < 0) { > > > + dev_err(bus->dev, "Bank switch failed: %d\n", ret); > > > + return ret; > > > + } > > > + > > > + /* make sure alternate bank (previous current) is also disabled */ > > > + list_for_each_entry(m_rt, &stream->master_list, stream_node) { > > > + bus = m_rt->bus; > > > + /* Disable port(s) */ > > > + ret = sdw_enable_disable_ports(m_rt, false); > > > + if (ret < 0) { > > > + dev_err(bus->dev, "Disable port(s) failed: %d\n", ret); > > > + return ret; > > > + } > > > + } > > > + > > > + return 0; > > > } > > > /** > > > -- > > > 2.20.1 > > > > > --