[Intel-gfx] [PATCH v2 21/24] drm/i915/display: Move verbose_state_checks under display

[Hogander, Jouni]

On Tue, 2023-10-24 at 15:12 +0300, Jani Nikula wrote:
> On Tue, 24 Oct 2023, Luca Coelho <luca at coelho.fi> wrote:
> > On Tue, 2023-10-24 at 08:22 +0000, Hogander, Jouni wrote:
> > > On Mon, 2023-10-23 at 17:00 +0300, Luca Coelho wrote:
> > > > On Mon, 2023-10-16 at 14:16 +0300, Jouni Högander wrote:
> > > > > Signed-off-by: Jouni Högander <jouni.hogander at intel.com>
> > > > > ---
> > > > >  drivers/gpu/drm/i915/display/intel_display.h        | 2 +-
> > > > >  drivers/gpu/drm/i915/display/intel_display_params.c | 3 +++
> > > > >  drivers/gpu/drm/i915/display/intel_display_params.h | 1 +
> > > > >  drivers/gpu/drm/i915/i915_params.c                  | 3 ---
> > > > >  drivers/gpu/drm/i915/i915_params.h                  | 1 -
> > > > >  5 files changed, 5 insertions(+), 5 deletions(-)
> > > > > 
> > > > > diff --git a/drivers/gpu/drm/i915/display/intel_display.h
> > > > > b/drivers/gpu/drm/i915/display/intel_display.h
> > > > > index ba3548f9768d..bc95fb377386 100644
> > > > > --- a/drivers/gpu/drm/i915/display/intel_display.h
> > > > > +++ b/drivers/gpu/drm/i915/display/intel_display.h
> > > > > @@ -552,7 +552,7 @@ bool assert_port_valid(struct
> > > > > drm_i915_private
> > > > > *i915, enum port port);
> > > > >         struct drm_device *drm = &(__i915)-
> > > > > > drm;                        \
> > > > >         int __ret_warn_on =
> > > > > !!(condition);                              \
> > > > >         if
> > > > > (unlikely(__ret_warn_on))                                    
> > > > > \
> > > > > -               if (!drm_WARN(drm, __i915-
> > > > > > params.verbose_state_checks, format)) \
> > > > > +               if (!drm_WARN(drm, __i915-
> > > > > > display.params.verbose_state_checks, format)) \
> > > > >                         drm_err(drm,
> > > > > format);                           \
> > > > >         unlikely(__ret_warn_on);                             
> > > > >       
> > > > >      \
> > > > >  })
> > > > > diff --git
> > > > > a/drivers/gpu/drm/i915/display/intel_display_params.c
> > > > > b/drivers/gpu/drm/i915/display/intel_display_params.c
> > > > > index 06e68c7fec1c..e86766639396 100644
> > > > > --- a/drivers/gpu/drm/i915/display/intel_display_params.c
> > > > > +++ b/drivers/gpu/drm/i915/display/intel_display_params.c
> > > > > @@ -87,6 +87,9 @@
> > > > > intel_display_param_named_unsafe(force_reset_modeset_test,
> > > > > bool,
> > > > > 0400,
> > > > >  intel_display_param_named(disable_display, bool, 0400,
> > > > >         "Disable display (default: false)");
> > > > >  
> > > > > +intel_display_param_named(verbose_state_checks, bool, 0400,
> > > > > +       "Enable verbose logs (ie. WARN_ON()) in case of
> > > > > unexpected
> > > > > hw state conditions.");
> > > > > +
> > > > >  intel_display_param_named_unsafe(enable_fbc, int, 0400,
> > > > >         "Enable frame buffer compression for power savings "
> > > > >         "(default: -1 (use per-chip default))");
> > > > > diff --git
> > > > > a/drivers/gpu/drm/i915/display/intel_display_params.h
> > > > > b/drivers/gpu/drm/i915/display/intel_display_params.h
> > > > > index 60d9c3d59fe4..b35443f51375 100644
> > > > > --- a/drivers/gpu/drm/i915/display/intel_display_params.h
> > > > > +++ b/drivers/gpu/drm/i915/display/intel_display_params.h
> > > > > @@ -39,6 +39,7 @@ struct drm_i915_private;
> > > > >         param(bool, load_detect_test, false, 0600) \
> > > > >         param(bool, force_reset_modeset_test, false, 0600) \
> > > > >         param(bool, disable_display, false, 0400) \
> > > > > +       param(bool, verbose_state_checks, true, 0) \
> > > > 
> > > > Why is this one 0? Why can't we even read it?
> > > 
> > > I found this comment in older commit message written by Jani
> > > Nikula:
> > > 
> > > "0 mode will bypass debugfs creation. Use it for
> > > verbose_state_checks
> > > which will need special attention in follow-up work."
> > 
> > This sounds pretty odd, why wouldn't we want it to be even read?
> 
> I *think* I remember why.
> 
> When I added the device parameters, I915_STATE_WARN(), the only user
> of
> verbose_state_checks, did not have the i915 parameter yet. So it
> could
> not access the device parameter.
> 
> Thus the verbose_state_checks *module* parameter had to have 0600
> mode,
> and modifying that runtime meant that the *device* parameter, even as
> read-only, would have gone out of sync and shown a different value.
> 
> I only added the i915 parameter to I915_STATE_WARN() last May, but
> clearly did not follow through with the parameter change.
> 
> From now on, it should use the device param like the rest of the
> code,
> it should have a mutable debugfs file, and the module parameter
> should
> be 0400.

Ok, I will still do this change and resend.

BR,

Jouni Högander

> 
> 
> BR,
> Jani.
> 
> 
> > 
> > In any case, it's not related to this patch, so:
> > 
> > Reviewed-by: Luca Coelho <luciano.coelho at intel.com>
> > 
> > --
> > Cheers,
> > Luca.
> 
> -- 
> Jani Nikula, Intel