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From: Timur Tabi <timur@codeaurora.org>
To: Pratyush Anand <panand@redhat.com>
Cc: Guenter Roeck <linux@roeck-us.net>,
	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>, Wim Van Sebroeck <wim@iguana.be>
Subject: Re: [PATCH RFC] Watchdog: sbsa_gwdt: Enhance timeout range
Date: Wed, 4 May 2016 11:17:29 -0500	[thread overview]
Message-ID: <572A2099.4070901@codeaurora.org> (raw)
In-Reply-To: <20160504155932.GH13045@dhcppc6.redhat.com>

Pratyush Anand wrote:
> Its unique to SBSA because you have very little timeout here. kexec-tools
> upstream does not have any mechanism to handle watchdog timeout. Lets say even
> if we implement a framework there, the best it can do is to ping the watchdog
> again.

Ok, so it's more accurate to say that kexec has a minimum watchdog 
timeout requirement.  What happens if the system admin sets the timeout 
to 5 seconds arbitrarily?  The system will reset during kexec, no matter 
which hardware is used.

This still sounds like a band-aid to me.  We're just assuming that we 
need a timeout of at least 20 seconds to support kexec.  Frankly, this 
still sounds like a problem the kexec developers needs to acknowledge 
and deal with.

Still I'm okay with a patch that extends the timeout by programming WCV, 
but it has to be commented as a hack specifically to support kexec 
because the timeout might be too short.  Then Wim can decide whether he 
supports such changes.

-- 
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: Wed, 4 May 2016 11:17:29 -0500	[thread overview]
Message-ID: <572A2099.4070901@codeaurora.org> (raw)
In-Reply-To: <20160504155932.GH13045@dhcppc6.redhat.com>

Pratyush Anand wrote:
> Its unique to SBSA because you have very little timeout here. kexec-tools
> upstream does not have any mechanism to handle watchdog timeout. Lets say even
> if we implement a framework there, the best it can do is to ping the watchdog
> again.

Ok, so it's more accurate to say that kexec has a minimum watchdog 
timeout requirement.  What happens if the system admin sets the timeout 
to 5 seconds arbitrarily?  The system will reset during kexec, no matter 
which hardware is used.

This still sounds like a band-aid to me.  We're just assuming that we 
need a timeout of at least 20 seconds to support kexec.  Frankly, this 
still sounds like a problem the kexec developers needs to acknowledge 
and deal with.

Still I'm okay with a patch that extends the timeout by programming WCV, 
but it has to be commented as a hack specifically to support kexec 
because the timeout might be too short.  Then Wim can decide whether he 
supports such changes.

-- 
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:[~2016-05-04 16:17 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 [this message]
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
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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