From: Nishanth Menon <nm@ti.com>
To: Joshua Emele <jemele@gmail.com>
Cc: Kevin Hilman <khilman@ti.com>, "Rafael J. Wysocki" <rjw@sisk.pl>,
linux-omap@vger.kernel.org, cpufreq@vger.kernel.org,
linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/4] cpufreq: OMAP: if an iva clock name is specified, load iva resources
Date: Wed, 7 Nov 2012 08:53:52 -0600 [thread overview]
Message-ID: <20121107145352.GA15742@kahuna> (raw)
In-Reply-To: <1352252861-18384-2-git-send-email-jemele@gmail.com>
On 17:47-20121106, Joshua Emele wrote:
> +static int __cpuinit omap_iva_init(struct cpufreq_policy *policy)
> +{
> + int result;
> + if (!iva_clk_name) {
> + pr_info("%s: iva unavailable\n", __func__);
> + return 0;
> + }
> + iva_dev = omap_device_get_by_hwmod_name("iva");
NAK. Reasons as follows:
a) cpufreq is purely meant for cpu, not IVA. we should instead be using
devfreq which is designed around the usage for co-processor
b) clubbing ARM's frequency decision is definitely NOT equal to IVA
frequency decision, not only is it wrong in terms of modularization, it
is wrong in terms of power benefits as well (not to mention weirdness
needed when you look at all OMAP SoC variants)
c) DVFS is not trivial around multiple co-processor transitions -> core
OPPs (as dependent OPP) needs to be addressed as well. ideally common
clock framework could take care of clock dependencies.
--
Regards,
Nishanth Menon
next prev parent reply other threads:[~2012-11-07 14:53 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-07 1:47 [PATCH 0/4] cpufreq: OMAP: if available, scale the iva coprocessor Joshua Emele
2012-11-07 1:47 ` [PATCH 1/4] cpufreq: OMAP: if an iva clock name is specified, load iva resources Joshua Emele
2012-11-07 14:53 ` Nishanth Menon [this message]
[not found] ` <CALH_86ST1kF_csak_75Dk7dDupOqdCT=H11MKBeLsiyqi5vd_w@mail.gmail.com>
2012-11-07 21:07 ` Nishanth Menon
2012-11-07 1:47 ` [PATCH 2/4] cpufreq: OMAP: for omap3 devices, specify the iva clock name Joshua Emele
2012-11-07 1:47 ` [PATCH 3/4] cpufreq: OMAP: ensure the iva coprocessor is at the same opp as the mpu Joshua Emele
2012-11-07 1:47 ` [PATCH 4/4] cpufreq: OMAP: scale the iva coprocessor if available Joshua Emele
2012-11-07 14:42 ` [PATCH 0/4] cpufreq: OMAP: if available, scale the iva coprocessor Santosh Shilimkar
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