Re: [RFC][PATCH] misc: Introduce reboot_reason driver

On Tue, Dec 8, 2015 at 4:15 PM, Bjorn Andersson
[off-list ref] wrote:

On Tue 08 Dec 13:52 PST 2015, Arnd Bergmann wrote:

quoted

On Tuesday 08 December 2015 13:29:22 John Stultz wrote:

[...]

quoted

quoted

+static int __init reboot_reason_init(void)
+{
+   return platform_driver_register(&reboot_reason_driver);
+}
+arch_initcall(reboot_reason_init);

Why this early? If it can be a normal device_initcall, you can use
module_platform_driver().

Not represented in this patch is that several Android vendors uses this
mechanism to communicate a panic() to the boot loader; to let the system
enter some sort of memory dump state.

They could also just parse pstore and look for a panic(). Or the
bootloader should set the reason to enter memory dump and the kernel
should clear it once it is up enough to handle resets. You have a
window of time already that a panic will hang. Only a watchdog will
help there and that would need a different solution.

Are panics in early boot really common outside of development?

Rob