From: Vinod Koul <vinod.koul-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
To: Laxman Dewangan <ldewangan-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
Cc: "dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org"
<dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
"linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>,
"linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: [PATCH] dma: tegra: enable/disable dma clock
Date: Fri, 20 Jul 2012 12:10:45 +0530 [thread overview]
Message-ID: <1342766445.1726.246.camel@vkoul-udesk3> (raw)
In-Reply-To: <5008F4D8.9070108-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
On Fri, 2012-07-20 at 11:34 +0530, Laxman Dewangan wrote:
> On Friday 20 July 2012 11:32 AM, Vinod Koul wrote:
> > On Wed, 2012-07-18 at 14:26 +0530, Laxman Dewangan wrote:
> >> Enable the DMA clock when registering DMA driver and
> >> disable clock when removing the DMA driver.
> >>
> >> The failure was observed on Tegra20 based system by
> >> Stephen Warren. However, it is working fine on tegra30
> >> based system and probably becasue uboot enable the clock
> >> on Tegra30.
> > Don't know much about the clock subsystem, but shouldn't the clocks be
> > enabled runtime..... when you actually start using the controller??
>
> Yes, this is the plan and I am going to implement dynamic clock
> management but it will take some time to complete and have testing
> throughly. some of the issue which I am seeing and analyzing on this
> approach is that
> - clock disable can be called from isr context or not?
> - how much complexity will be added in dma driver to implement this?
> - What power benefit we will get on this.
> - Is there any user which generally use dma and always keep dma on
> requested state like UART RX always ready etc.
>
> So keeping that in mind, it will take some time to complete this and
> meanwhile, I want to make it work for Tegra20 based system which is not
> working on current driver.
> and hence this is the change.
for a start you can move these to .alloc_chan_resources
and .free_chan_resources while doing a refcount.
Further optimization can be done by moving this to tx_submit and
tasklet.
--
~Vinod
WARNING: multiple messages have this Message-ID (diff)
From: Vinod Koul <vinod.koul@linux.intel.com>
To: Laxman Dewangan <ldewangan@nvidia.com>
Cc: "dan.j.williams@intel.com" <dan.j.williams@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Stephen Warren <swarren@nvidia.com>,
"linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>
Subject: Re: [PATCH] dma: tegra: enable/disable dma clock
Date: Fri, 20 Jul 2012 12:10:45 +0530 [thread overview]
Message-ID: <1342766445.1726.246.camel@vkoul-udesk3> (raw)
In-Reply-To: <5008F4D8.9070108@nvidia.com>
On Fri, 2012-07-20 at 11:34 +0530, Laxman Dewangan wrote:
> On Friday 20 July 2012 11:32 AM, Vinod Koul wrote:
> > On Wed, 2012-07-18 at 14:26 +0530, Laxman Dewangan wrote:
> >> Enable the DMA clock when registering DMA driver and
> >> disable clock when removing the DMA driver.
> >>
> >> The failure was observed on Tegra20 based system by
> >> Stephen Warren. However, it is working fine on tegra30
> >> based system and probably becasue uboot enable the clock
> >> on Tegra30.
> > Don't know much about the clock subsystem, but shouldn't the clocks be
> > enabled runtime..... when you actually start using the controller??
>
> Yes, this is the plan and I am going to implement dynamic clock
> management but it will take some time to complete and have testing
> throughly. some of the issue which I am seeing and analyzing on this
> approach is that
> - clock disable can be called from isr context or not?
> - how much complexity will be added in dma driver to implement this?
> - What power benefit we will get on this.
> - Is there any user which generally use dma and always keep dma on
> requested state like UART RX always ready etc.
>
> So keeping that in mind, it will take some time to complete this and
> meanwhile, I want to make it work for Tegra20 based system which is not
> working on current driver.
> and hence this is the change.
for a start you can move these to .alloc_chan_resources
and .free_chan_resources while doing a refcount.
Further optimization can be done by moving this to tx_submit and
tasklet.
--
~Vinod
next prev parent reply other threads:[~2012-07-20 6:40 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-18 8:56 [PATCH] dma: tegra: enable/disable dma clock Laxman Dewangan
2012-07-18 8:56 ` Laxman Dewangan
[not found] ` <1342601769-13852-1-git-send-email-ldewangan-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2012-07-20 6:02 ` Vinod Koul
2012-07-20 6:02 ` Vinod Koul
2012-07-20 6:04 ` Laxman Dewangan
2012-07-20 6:04 ` Laxman Dewangan
[not found] ` <5008F4D8.9070108-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2012-07-20 6:40 ` Vinod Koul [this message]
2012-07-20 6:40 ` Vinod Koul
2012-07-20 6:34 ` Laxman Dewangan
2012-07-20 6:34 ` Laxman Dewangan
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1342766445.1726.246.camel@vkoul-udesk3 \
--to=vinod.koul-vuqaysv1563yd54fqh9/ca@public.gmane.org \
--cc=dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org \
--cc=ldewangan-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org \
--cc=linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.