Messages in this thread | | | From | Saravana Kannan <> | Date | Tue, 14 Sep 2021 10:31:30 -0700 | Subject | Re: [PATCH v1 5/5] driver core: Add fw_devlink.debug command line boolean parameter |
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On Tue, Sep 14, 2021 at 9:52 AM Rob Herring <robh+dt@kernel.org> wrote: > > On Tue, Sep 14, 2021 at 11:44 AM Andrew Lunn <andrew@lunn.ch> wrote: > > > > > I did think of this, but the problem is that dynamic debug logs can > > > get compiled out (when DYNAMIC_DEBUG isn't set). I think debugging of > > > fw_devlink needs to be possible without having to recompile the > > > kernel. So in a sense similar to how initcall_debug works today. > > > > My off the shelf Debian kernel has it enabled. Maybe you can check > > other mainline distributions and see if it is enabled by default. > > Right, I would expect users that can't rebuild their kernel easily > would have it enabled. > > > You are also on a slippery path. You argue this is needed all the time > > and add a custom knob. Somebody else adds a new feature which they > > also argue always needs bug, and add there own custom knob. We soon > > have lots of custom knobs, each doing it slightly differently, in > > different places. Chaos. So you need a really good argument why your > > code really is special. > > > > I would suggest you start with dynamic debug, and collect some > > statistics of how often you need to ask people to recompile their > > kernel. > > I agree.
Fair enough -- Andrew/Rob.
> > What would be nice is documenting what needs to be set for devlink. > What I used was just 'dyndbg="file drivers/base/core.c +p"'
Yeah, I was thinking if we went with dynamic debug I'd have something I'll copy paste as a reply to any fw_devlink debug email thread.
Where would be a good place to document this?
I was actually thinking of making fw_devlink.debug=1 be an alias for something like: dyndbg="func device_link_add +p; func device_links_check_suppliers +p"....
So that people don't have to remember what to copy paste into their command line as things change.
-Saravana
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