Am 2020-09-24 15:19, schrieb Tom Rini:
On Thu, Sep 24, 2020 at 09:33:50AM +0200, Michael Walle wrote:
Am 2020-09-23 19:35, schrieb Tom Rini:
[..]
> > Not printf(), maybe log_info().
> >
> > The disabling has to occur in ExitBootServices() (aka.
> > efi_exit_boot_services()). Here we are in the middle of an executing
> > UEFI application. Printing anything on the screen may mess up the
> > output
> > of the UEFI application.
> >
> > So, please, don't output anything.
>
> We need to find a good way to inform the user we're disabling their
> watchdog. Maybe before we fully jump in to UEFI note that it will be
> disabled before entering the OS? Or something a bit more generally
> understood than ExitBootServices() having been called. I don't know
> _where_ the best place is, but I think it's important to inform the
> user.
The watchdog is only disabled in the "supervise u-boot" mode, why
would we need to inform the user? It was the users choice to have
the timer only enabled in u-boot.
Or do you mean if for example the vendor chooses that option and
in this case the user doesn't know anything about it? The mode
is indicated in the "WDT:" output.
I'm talking about the case where we say we've enabled the WDT to
supervise OS, but then bootefi something and have disabled the watchdog
(to meet UEFI requirements) but didn't tell the user we've turned off
the WDT that we had told them is on.
Ah, do you really want to have a different behavior between bootm and
bootefi? Thats even more suprising IMHO.
I had the following in mind:
+config WATCHDOG_SUPERVISE_OS
+ bool "Supervise U-boot and operating system"
+ help
+ Upon U-Boot startup the first watchdog will be started
automatically
+ and kept running even after booting the operating system.
+ Be aware, that the operating system needs to service the
watchdog!
+
+ Additionally, this is not UEFI compliant because:
+ - the timeout won't be set to 5 minutes before starting the
OS and
+ - the watchdog timer isn't stopped after the OS calls
+ ExitBootServices().
-michael
