From: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
To: Zidan Wang <zidan.wang@freescale.com>
Cc: alsa-devel@alsa-project.org, broonie@kernel.org,
patches@opensource.wolfsonmicro.com
Subject: Re: wm8960 sleep time is too long when system suspend
Date: Mon, 2 Nov 2015 09:18:55 +0000 [thread overview]
Message-ID: <20151102091855.GO10520@ck-lbox> (raw)
In-Reply-To: <20151102084402.GA7603@shlinux2>
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.
Thanks,
Charles
next prev parent reply other threads:[~2015-11-02 9:34 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-02 8:44 wm8960 sleep time is too long when system suspend Zidan Wang
2015-11-02 9:18 ` Charles Keepax [this message]
2015-11-02 10:49 ` Zidan Wang
2015-11-02 11:16 ` Mark Brown
2015-11-02 11:12 ` Mark Brown
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