From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vinod Koul Subject: Re: [PATCH v3] ALSA: core: let low-level driver or userspace disable rewinds Date: Mon, 19 Jun 2017 13:33:47 +0530 Message-ID: <20170619080347.GI19154@localhost> References: <1497853357-2931-1-git-send-email-subhransu.s.prusty@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by alsa0.perex.cz (Postfix) with ESMTP id 291F9266DCC for ; Mon, 19 Jun 2017 10:01:07 +0200 (CEST) Content-Disposition: inline In-Reply-To: <1497853357-2931-1-git-send-email-subhransu.s.prusty@intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: "Subhransu S. Prusty" Cc: alsa-devel@alsa-project.org, tiwai@suse.de, lgirdwood@gmail.com, Ramesh Babu , Pierre-Louis Bossart , patches.audio@intel.com, broonie@kernel.org List-Id: alsa-devel@alsa-project.org On Mon, Jun 19, 2017 at 11:52:37AM +0530, Subhransu S. Prusty wrote: > From: Pierre-Louis Bossart > > Add new hw_params flag to explicitly tell driver that rewinds will never > be used. This can be used by low-level driver to optimize DMA operations > and reduce power consumption. Use this flag only when data written in > ring buffer will never be invalidated, e.g. any update of appl_ptr is > final. > > Note that the update of appl_ptr include both a read/write data > operation as well as snd_pcm_forward() whose behavior is not modified. Reviewed-By: Vinod Koul -- ~Vinod