Re: [PATCH v5 2/3] venus: Add a debugfs file for SSR trigger
From: dikshita
Date: Thu Sep 16 2021 - 02:29:48 EST
On 2021-09-16 01:09, Stephen Boyd wrote:
Quoting dikshita@xxxxxxxxxxxxxx (2021-09-15 02:13:09)
Hi Stephen,
Reviving the discussion on this change as we need to pull this in.
As per your suggestion, I explored the fault injection framework to
implement this functionality.
But I don't think that meets our requirements.
We need a way to trigger subsystem restart from the client-side, it's
not derived from the driver.
Just to confirm, this is all for debugging purposes right?
yes, correct. this is for debugging purposes. We need this to simulate
an error on FW side.
In a normal scenario, when FW runs into error, sys error is triggered
from FW as result of which
a sequence of commands are followed for restarting the system.
using this feature, we are trying to simulate this error on FW i.e we
are forcing the FW to run into an error.
while fault injection framework enables the driver to trigger an
injection
when a specific event occurs for eg: page allocation failure or memory
access failure.
So, IMO, we will have to use custom debugfs only.
Can you use DECLARE_FAULT_ATTR()? Or you need it to be active instead
of
passive, i.e. it shouldn't wait for should_fail() to return true, but
actively trigger something on the remoteproc?
yes, it doesn't need to wait for should_fail() to return true.
the client/user should be able to trigger this subsystem restart(SSR) at
any point of time
when a session is running. It's totally client-driven.
Please feel free to correct me in case my understanding of the
framework
is wrong.
I presume the fault injection framework could get a new feature that
lets the fault be injected immediately upon writing the debugfs file.
My goal is to consolidate this sort of logic into one place and then
put
it behind some config option that distros can disable so the kernel
isn't bloated with debug features that end users will never care about.