From: Timur Tabi <timur@codeaurora.org>
To: Guenter Roeck <linux@roeck-us.net>, Pratyush Anand <panand@redhat.com>
Cc: linux-watchdog@vger.kernel.org, kexec@lists.infradead.org,
open list <linux-kernel@vger.kernel.org>,
wim@iguana.be, fu.wei@linaro.org, Suravee.Suthikulpanit@amd.com,
Dave Young <dyoung@redhat.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH RFC] Watchdog: sbsa_gwdt: Enhance timeout range
Date: Thu, 5 May 2016 18:45:52 -0500 [thread overview]
Message-ID: <572BDB30.9060602@codeaurora.org> (raw)
In-Reply-To: <572BD959.3090507@codeaurora.org>
Timur Tabi wrote:
>
>> A 32-bit counter is absolutely fine. Letting it run with a 400MHz clock
>> (or was it 200 MHz ?) is the problem. A resolution of 2.5ns for a
>> watchdog
>> timer does not really make any sense.
>
> The 10 second limit is based on a 20MHz clock.
No, that's not true. I misread the code. I knew something was wrong,
but it didn't click until just now.
The default timeout is 10 seconds. The max timeout on a 20MHz system
(which is what we're running) is over 200 seconds.
The problem is that Pratyush's system is running at a clock that's way
too fast:
[ 131.187562] sbsa-gwdt sbsa-gwdt.0: Initialized with 40s timeout @
250000000 Hz, action=1.
250MHz is unreasonable. Pratyush, why is your system counter so high?
On our ARM64 system, it's set to 20MHz.
--
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
Forum, a Linux Foundation collaborative project.
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next prev parent reply other threads:[~2016-05-05 23:45 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <5728A7C3.4010001@roeck-us.net>
[not found] ` <20160503143856.GE13045@dhcppc6.redhat.com>
[not found] ` <5728BEC4.6050603@codeaurora.org>
[not found] ` <20160503155141.GF13045@dhcppc6.redhat.com>
[not found] ` <20160503171602.GA2518@roeck-us.net>
[not found] ` <20160504141449.GG13045@dhcppc6.redhat.com>
[not found] ` <572A0577.1070000@codeaurora.org>
[not found] ` <20160504155932.GH13045@dhcppc6.redhat.com>
[not found] ` <572A2099.4070901@codeaurora.org>
[not found] ` <20160505164300.GA16914@roeck-us.net>
2016-05-05 18:20 ` [PATCH RFC] Watchdog: sbsa_gwdt: Enhance timeout range Pratyush Anand
2016-05-05 18:22 ` Timur Tabi
2016-05-05 23:36 ` Guenter Roeck
2016-05-05 23:38 ` Timur Tabi
2016-05-05 23:45 ` Timur Tabi [this message]
2016-05-06 0:18 ` Guenter Roeck
2016-05-05 23:51 ` Guenter Roeck
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