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

[Jani Nikula]

On Fri, 17 Mar 2023, Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:
> On Fri, Mar 17, 2023 at 04:30:37PM +0200, Ville Syrjälä wrote:
>> On Fri, Mar 17, 2023 at 03:37:09PM +0200, Jani Nikula wrote:
>> > On Fri, 17 Mar 2023, Ville Syrjälä <ville.syrjala at 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 at 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.
>
> Eg. if I just jump on some random machine an do
>
> # grep . crtc-1/*
> ...
> i915_pipe: 3
> ...
>
> Now I need to most likely count with my fingers
> to figure out I'm actually looking at pipe D :P

Fair enough, not unreasonable.

Is it enough to have just A, B, ... or do we go with explanatory text
like i915_current_bpc has "Current: %u\n"?

BR,
Jani.




>
>> 
>> > 
>> > > Either way, the series is:
>> > > Reviewed-by: Ville Syrjälä <ville.syrjala at 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

-- 
Jani Nikula, Intel Open Source Graphics Center