On Tue, 24 Oct 2023, Luca Coelho <l...@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.hogan...@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. BR, Jani. > > In any case, it's not related to this patch, so: > > Reviewed-by: Luca Coelho <luciano.coe...@intel.com> > > -- > Cheers, > Luca. -- Jani Nikula, Intel
