On 05/01/2014 05:38 PM, Corey Minyard wrote:
On 05/01/2014 08:58 AM, Don Zickus wrote:
Hi Corey,
I stumbled upon an issue with a partner of ours, where they booted their
machine and tried to load the ipmi_watchdog module by hand and it failed.
The reason it failed was that the iTCO watchdog driver was already loaded
and it registered the misc device /dev/watchdog first.
I looked at the ipmi watchdog driver and realized it was never converted
to the new watchdog framework where the watchdog_core module manages the
'/dev/watchdog' misc device.
So being naive and not knowing much about IPMI, I decided to follow the
helpful document Documentation/watchdog/convert_drivers_to_kernel_api.txt
and convert the ipmi_watchdog to use the new watchdog framework.
I ran into a few issues and then realized the driver itself never really
binds to any hardware, so it makes the conversion process a little more
challenging.
So a few questions to you before I waste my time in this area:
- Is there any prior history about why the ipmi_watchdog was never
converted to the new watchdog framework? Lack of interest? Technical
hurdles?
Mostly lack of interest, but there are some technical hurdles.
It would be hard to implement some things. The watchdog framework has
no concept of pretimeouts. And IPMI is message based, you send a
Are you saying that WDIOC_SETPRETIMEOUT and WDIOC_GETPRETIMEOUT don't work
for ipmi ? If so, can you explain ?
message to a controller to do anything, and you have to wait for the
response. That doesn't work very well with the watchdog interface,
which assumes you can do everything immediately.
Does it ? How so ? Please elaborate; I don't immediately see how the watchdog
subsystem would prevent you from using, say, kernel threads or delayed workers
to implement asynchronous access to or from any underlying hardware.
Guenter
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