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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.

_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

WARNING: multiple messages have this Message-ID (diff)
From: Timur Tabi <timur@codeaurora.org>
To: Guenter Roeck <linux@roeck-us.net>, Pratyush Anand <panand@redhat.com>
Cc: fu.wei@linaro.org, Suravee.Suthikulpanit@amd.com, wim@iguana.be,
	linux-arm-kernel@lists.infradead.org,
	linux-watchdog@vger.kernel.org,
	open list <linux-kernel@vger.kernel.org>,
	Dave Young <dyoung@redhat.com>,
	kexec@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.

WARNING: multiple messages have this Message-ID (diff)
From: timur@codeaurora.org (Timur Tabi)
To: linux-arm-kernel@lists.infradead.org
Subject: [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.

  reply	other threads:[~2016-05-05 23:45 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-03  8:20 [PATCH RFC] Watchdog: sbsa_gwdt: Enhance timeout range Pratyush Anand
2016-05-03  8:20 ` Pratyush Anand
2016-05-03 12:12 ` Timur Tabi
2016-05-03 12:12   ` Timur Tabi
2016-05-03 13:24   ` Pratyush Anand
2016-05-03 13:24     ` Pratyush Anand
2016-05-03 13:47     ` Guenter Roeck
2016-05-03 13:47       ` Guenter Roeck
2016-05-03 14:17       ` Pratyush Anand
2016-05-03 14:17         ` Pratyush Anand
2016-05-03 14:46         ` Guenter Roeck
2016-05-03 14:46           ` Guenter Roeck
2016-05-03 15:04           ` Timur Tabi
2016-05-03 15:04             ` Timur Tabi
2016-05-03 13:29 ` Guenter Roeck
2016-05-03 13:29   ` Guenter Roeck
2016-05-03 14:38   ` Pratyush Anand
2016-05-03 14:38     ` Pratyush Anand
2016-05-03 15:07     ` Timur Tabi
2016-05-03 15:07       ` Timur Tabi
2016-05-03 15:51       ` Pratyush Anand
2016-05-03 15:51         ` Pratyush Anand
2016-05-03 17:16         ` Guenter Roeck
2016-05-03 17:16           ` Guenter Roeck
2016-05-04 14:14           ` Pratyush Anand
2016-05-04 14:14             ` Pratyush Anand
2016-05-04 14:21             ` Timur Tabi
2016-05-04 14:21               ` Timur Tabi
2016-05-04 15:59               ` Pratyush Anand
2016-05-04 15:59                 ` Pratyush Anand
2016-05-04 16:17                 ` Timur Tabi
2016-05-04 16:17                   ` Timur Tabi
2016-05-05 16:43                   ` Guenter Roeck
2016-05-05 16:43                     ` Guenter Roeck
2016-05-05 18:20                     ` Pratyush Anand
2016-05-05 18:20                       ` Pratyush Anand
2016-05-05 18:20                       ` Pratyush Anand
2016-05-05 18:22                       ` Timur Tabi
2016-05-05 18:22                         ` Timur Tabi
2016-05-05 18:22                         ` Timur Tabi
2016-05-05 23:36                         ` Guenter Roeck
2016-05-05 23:36                           ` Guenter Roeck
2016-05-05 23:36                           ` Guenter Roeck
2016-05-05 23:38                           ` Timur Tabi
2016-05-05 23:38                             ` Timur Tabi
2016-05-05 23:38                             ` Timur Tabi
2016-05-05 23:45                             ` Timur Tabi [this message]
2016-05-05 23:45                               ` Timur Tabi
2016-05-05 23:45                               ` Timur Tabi
2016-05-06  0:18                               ` Guenter Roeck
2016-05-06  0:18                                 ` Guenter Roeck
2016-05-06  0:18                                 ` Guenter Roeck
2016-05-05 23:51                             ` Guenter Roeck
2016-05-05 23:51                               ` Guenter Roeck
2016-05-05 23:51                               ` Guenter Roeck

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