From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zidan Wang Subject: Re: wm8960 sleep time is too long when system suspend Date: Mon, 2 Nov 2015 18:49:23 +0800 Message-ID: <20151102104921.GA4769@shlinux2> References: <20151102084402.GA7603@shlinux2> <20151102091855.GO10520@ck-lbox> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from na01-bl2-obe.outbound.protection.outlook.com (mail-bl2on0110.outbound.protection.outlook.com [65.55.169.110]) by alsa0.perex.cz (Postfix) with ESMTP id DDC1B2607C8 for ; Mon, 2 Nov 2015 11:51:16 +0100 (CET) Content-Disposition: inline In-Reply-To: <20151102091855.GO10520@ck-lbox> 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: Charles Keepax Cc: alsa-devel@alsa-project.org, broonie@kernel.org, patches@opensource.wolfsonmicro.com List-Id: alsa-devel@alsa-project.org On Mon, Nov 02, 2015 at 09:18:55AM +0000, Charles Keepax wrote: > On Mon, Nov 02, 2015 at 04:44:04PM +0800, Zidan Wang wrote: > > Hi Mark, > > > > In wm8960 codec driver, suspend_bias_off has been enabled. So when system suspend, the wm8960 codec will go to bias off, > > it will disable VMID and VREF, then sleep 600ms. It seems that 600ms is too long for system suspend. > > > > Because the wm8960 datasheet don't mentioned the sleep time, so i want to check with you if we can shorten the sleep time. > > I can't say that I am explicit familiar with the required delay > there, but the comment in the code says that we are letting VMID > and VREF discharge, which I certainly could believe would take a > while. My guess would be that we likely weren't super excited > about putting a 600mS delay in, which probably means it was > necessary for some reason. > > How much where you hoping to reduce it by? I can see if I can > find a hardware engineer who still remembers enough about the > part to discuss it with. > Some customer can't accept such long system suspend time. It's better to spend less than 100ms for system suspend. Codec suspend is a part of system suspend, so it should be less than 100ms, and as short as possible. Best Regards, Zidan Wang > Thanks, > Charles