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 Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 668BBC433EF for ; Fri, 4 Mar 2022 08:45:17 +0000 (UTC) Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id A8E6E185E; Fri, 4 Mar 2022 09:44:25 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz A8E6E185E DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1646383515; bh=btdIYxnkQ3rbF3WfjxYfQWXkOrtofB6mb5hpCkxJsKo=; h=Date:From:To:Subject:In-Reply-To:References:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=vl4jYsoB5fOZnpfqmJ9eD0QXiyyW5+65s+y1djQCaLlXPCJpbQnffvQCPjFWCw34s 8Kxv29+KIYGxwtI/I6UBl3AekhbMhj50JY1M79Lhw6Q3jUQgGcxSmrEeZpoyWmNapo 4Wfj3Wrfz+mxApWa6040B54jRCn867STRgeoDoJ0= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id 3BB36F800F2; Fri, 4 Mar 2022 09:44:25 +0100 (CET) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 596FBF800F2; Fri, 4 Mar 2022 09:44:23 +0100 (CET) Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id D1ED9F800F2 for ; Fri, 4 Mar 2022 09:44:16 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz D1ED9F800F2 Authentication-Results: alsa1.perex.cz; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="zcqChJiI"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="rw/dH8Rz" Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id 6032321115; Fri, 4 Mar 2022 08:44:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1646383456; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=laZCxCImG/PcxqdShUBHqM4Li3kIMMy3VJIir8N3ihY=; b=zcqChJiIVMyMGNutPjpvUV3X0V5FWCyfoEl2xjQLu7gkXcJS4LM5Dr6jWx9CXzNMIZv6// MszRwFxZGteNattGSc1bv8e1z384fhRm7DLSeryMfXpH+Nx5VMyUqu1IwFRlZ4XJpM3lRJ UxfocMjZV4YxRAYFJEepkyz0urxRZUQ= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1646383456; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=laZCxCImG/PcxqdShUBHqM4Li3kIMMy3VJIir8N3ihY=; b=rw/dH8Rz+ghigFFFeINI8zSr10YlJ3AnryHR0RwFoqC0JOQngdpW5QcZVFeKkSnsm8xSrB 0D/fZvoRu6qQCzAQ== Received: from alsa1.suse.de (alsa1.suse.de [10.160.4.42]) by relay2.suse.de (Postfix) with ESMTP id 56156A3B99; Fri, 4 Mar 2022 08:44:16 +0000 (UTC) Date: Fri, 04 Mar 2022 09:44:16 +0100 Message-ID: From: Takashi Iwai To: "S.J. Wang" Subject: Re: Issue in pcm_dsnoop.c in alsa-lib In-Reply-To: References: User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.3 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Cc: Chancel Liu , "alsa-devel@alsa-project.org" , Shengjiu Wang X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" On Fri, 04 Mar 2022 09:35:28 +0100, S.J. Wang wrote: > > > > > > > > > Hi Takashi Iwai, Jaroslav Kysela > > > > > > We encountered an issue in the pcm_dsnoop use case, could you > > > please help to have a look? > > > > > > *Issue description:* > > > With two instances for dsnoop type device running in parallel, > > > after suspend/resume, one of the instances will be hung in memcpy > > > because the very large copy size is obtained. > > > > > > #3 0x0000ffffa78d5098 in snd_pcm_dsnoop_sync_ptr > > (pcm=0xaaab06563da0) > > > at pcm_dsnoop.c:158 dsnoop = 0xaaab06563c20 slave_hw_ptr = 64 > > > old_slave_hw_ptr = 533120 avail = *187651522444320* > > > > > > * Reason analysis: * > > > The root cause that I analysis is that after suspend/resume, one > > > instance will get the SND_PCM_STATE_SUSPENDED state from slave pcm > > device, > > > then it will do snd_pcm_prepare() and snd_pcm_start(), which will > > > reset the dsnoop->slave_hw_ptr and the hw_ptr of slave pcm device, > > > then the state of this instance is correct. But another instance may > > > not get the SND_PCM_STATE_SUSPENDED state from slave pcm device > > > because slave device may have been recovered by first instance, so > > > the dsnoop->slave_hw_ptr is not reset. but because hw_ptr of slave > > > pcm device has been reset, so there will be a very large "avail" size. > > > > > > *Solution:* > > > I didn't come up with a fix for this issue, seems there is no easy > > > way to let another instance know this case and reset the > > > dsnoop->slave_hw_ptr, could you please help? > > > > Could you try topic/pcm-direct-resume branch on > > > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub > > .com%2Ftiwai%2Falsa- > > lib&data=04%7C01%7Cshengjiu.wang%40nxp.com%7C95f97de3f2c840d > > 9853508d9fd2e79ea%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C > > 637819198319430045%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwM > > DAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdat > > a=WWX1ZlcQhJF3pHJdHPIH%2B0xG9o%2FjQnHG5fHDbKXwQwE%3D&r > > eserved=0 > > > > Thanks, I push my test result in https://github.com/alsa-project/alsa-lib/issues/213 > Could you please review? Please keep the discussion on ML. Takashi