Re: [Intel-gfx] [PATCH 2/2] drm/i915/debugfs: add crtc i915_pipe debugfs file

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Fri, Mar 17, 2023 at 03:37:09PM +0200, Jani Nikula wrote:
> On Fri, 17 Mar 2023, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote:
> > On Fri, Mar 17, 2023 at 02:53:52PM +0200, Jani Nikula wrote:
> >> The pipe may differ from crtc index if pipes are fused off. For testing
> >> purposes, IGT needs to know the pipe.
> >> 
> >> There's already a I915_GET_PIPE_FROM_CRTC_ID IOCTL for this. However,
> >> the upcoming Xe driver won't have that IOCTL, and going forward, we'll
> >> want a unified interface for testing i915 and Xe, as they share the
> >> display code. Thus add the debugfs for i915 display.
> >> 
> >> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> >> ---
> >>  .../gpu/drm/i915/display/intel_display_debugfs.c    | 13 +++++++++++++
> >>  1 file changed, 13 insertions(+)
> >> 
> >> diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> >> index faa44fb80aac..e85270adca95 100644
> >> --- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> >> +++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> >> @@ -1657,6 +1657,17 @@ static int i915_current_bpc_show(struct seq_file *m, void *data)
> >>  }
> >>  DEFINE_SHOW_ATTRIBUTE(i915_current_bpc);
> >>  
> >> +/* Pipe may differ from crtc index if pipes are fused off */
> >> +static int intel_crtc_pipe_show(struct seq_file *m, void *unused)
> >> +{
> >> +	struct intel_crtc *crtc = m->private;
> >> +
> >> +	seq_printf(m, "%d\n", crtc->pipe);
> >
> > Are we happy with an integer or should we use the actual alphabetic
> > name here?
> 
> Primarily I considered the programmatic use case, and the ease of
> switching over from the ioctl. What do we gain by making IGT parse this?

Well even the integer is represented in ascii so parsing
needs to happen anyway. But I was mainly thinking if any
human looks at it they may be confused as to what the
raw integer even means.

> 
> > Either way, the series is:
> > Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> Thanks,
> Jani.
> 
> >
> >> +
> >> +	return 0;
> >> +}
> >> +DEFINE_SHOW_ATTRIBUTE(intel_crtc_pipe);
> >> +
> >>  /**
> >>   * intel_connector_debugfs_add - add i915 specific connector debugfs files
> >>   * @connector: pointer to a registered drm_connector
> >> @@ -1735,4 +1746,6 @@ void intel_crtc_debugfs_add(struct intel_crtc *crtc)
> >>  
> >>  	debugfs_create_file("i915_current_bpc", 0444, root, crtc,
> >>  			    &i915_current_bpc_fops);
> >> +	debugfs_create_file("i915_pipe", 0444, root, crtc,
> >> +			    &intel_crtc_pipe_fops);
> >>  }
> >> -- 
> >> 2.39.2
> 
> -- 
> Jani Nikula, Intel Open Source Graphics Center

-- 
Ville Syrjälä
Intel