Re: [PATCH v9 00/53] fix CONFIG_DRM_USE_DYNAMIC_DEBUG=y

jim.cromie
2024-07-02T22:14:29Z

On Tue, Jul 2, 2024 at 4:01 PM Luis Chamberlain <mcgrof@kernel.org> wrote:
>
> On Tue, Jul 02, 2024 at 03:56:50PM -0600, Jim Cromie wrote:
> > This fixes dynamic-debug support for DRM.debug, added via classmaps.
> > commit bb2ff6c27bc9 (drm: Disable dynamic debug as broken)
> >
> > CONFIG_DRM_USE_DYNAMIC_DEBUG=y was marked broken because drm.debug=val
> > was applied when drm.ko was modprobed; too early for the yet-to-load
> > drivers, which thus missed the enablement. My testing with
> > /etc/modprobe.d/ entries and modprobes with dyndbg=$querycmd options
> > obscured this omission.
> >
> > The fix is to replace invocations of DECLARE_DYNDBG_CLASSMAP with
> > DYNDBG_CLASSMAP_DEFINE for core, and DYNDBG_CLASSMAP_USE for drivers.
> > The distinction allows dyndbg to also handle the users properly.
> >
> > DRM is the only current classmaps user, and is not really using it,
> > so if you think DRM could benefit from zero-off-cost debugs based on
> > static-keys, please test.
> >
> > HISTORY
> >
> > 9/4/22 - ee879be38bc8..ace7c4bbb240 commited - classmaps-v1 dyndbg parts
> > 9/11/22 - 0406faf25fb1..16deeb8e18ca commited - classmaps-v1 drm parts
> >
> > https://lore.kernel.org/lkml/Y3XUrOGAV4I7bB3M@kroah.com/
> > greg k-h says:
> > This should go through the drm tree now. The rest probably should also
> > go that way and not through my tree as well.
>
> Can't this just be defined as a coccinelle smpl patch? Must easier
> to read than 53 patches?
>

perhaps it could - Im not sure that would be easier to review
than a file-scoped struct declaration or reference per driver

Also, I did it hoping to solicit more Tested-by:s with drm.debug=0x1ff

Jim

> Luis
>