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[23.128.96.18]) by mx.google.com with ESMTP id m17si845898eds.398.2020.05.15.02.40.17; Fri, 15 May 2020 02:40:40 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@perex.cz header.s=default header.b=PjUdau40; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=perex.cz Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728061AbgEOJiF (ORCPT + 99 others); Fri, 15 May 2020 05:38:05 -0400 Received: from mail1.perex.cz ([77.48.224.245]:41316 "EHLO mail1.perex.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727785AbgEOJiE (ORCPT ); Fri, 15 May 2020 05:38:04 -0400 X-Greylist: delayed 417 seconds by postgrey-1.27 at vger.kernel.org; Fri, 15 May 2020 05:38:03 EDT Received: from mail1.perex.cz (localhost [127.0.0.1]) by smtp1.perex.cz (Perex's E-mail Delivery System) with ESMTP id 19E6AA0042; Fri, 15 May 2020 11:31:05 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp1.perex.cz 19E6AA0042 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=perex.cz; s=default; t=1589535065; bh=MZ3WhTdbJo0ZPJ+o1cwVqjMwYaFP9BgnkqanhewWYuU=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=PjUdau40OfvDTnmHt9dgKMWAuHci2F8LXEOo9nMfN/y9JCGOrFx8fvblnrUPPj0l8 vIyD+knHL5u52qs2A9AlbGPDzXgJP6QJwKkesTUYJQ2zeGQikKPATtlIXYyD9iHb66 EROLBakhgWLvIbCDpmIrt13sX8ruNJw48uhgHujI= Received: from p50.perex-int.cz (unknown [192.168.100.94]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: perex) by mail1.perex.cz (Perex's E-mail Delivery System) with ESMTPSA; Fri, 15 May 2020 11:30:54 +0200 (CEST) Subject: Re: [PATCH] ALSA: pcm: fix incorrect hw_base increase To: "Lu, Brent" , Greg Kroah-Hartman Cc: "alsa-devel@alsa-project.org" , Takashi Iwai , Baolin Wang , Arnd Bergmann , Richard Fontana , Thomas Gleixner , paulhsia , "linux-kernel@vger.kernel.org" References: <1589515779-20987-1-git-send-email-brent.lu@intel.com> <20200515070446.GA1226131@kroah.com> From: Jaroslav Kysela Message-ID: Date: Fri, 15 May 2020 11:30:54 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dne 15. 05. 20 v 11:04 Lu, Brent napsal(a): >> >> Is this a bugfix needed for older kernels as well? When did this issue show >> up? >> >> thanks, >> >> greg k-h > > It happens when DMA stop moving data from host to DSP/DAI for a long time > (> half of buffer time). I know host driver should do something about it. But if > not, the HWSYNC will keep increasing the hw_base and hw_ptr and confuses > user space program. I'm afraid, but with this code, you turn off the hw_ptr jiffies code. It would be better to fix the driver in this case (return the updated / estimated DMA pointer, increase DMA buffer size etc.). This "lag" is unacceptable. Jaroslav > > Regards, > Brent > -- Jaroslav Kysela Linux Sound Maintainer; ALSA Project; Red Hat, Inc.