Re: [PATCH 4/5] Add support for forcing 6 bpc on DP pipes.

Manasi Navare
2016-05-25T18:50:55Z

On Mon, May 23, 2016 at 10:42:41AM -0700, Jim Bride wrote:
> On Mon, May 23, 2016 at 11:22:17AM +0300, Ander Conselvan De Oliveira wrote:
> > On Fri, 2016-04-29 at 18:28 -0700, Manasi Navare wrote:
> > > From: Jim Bride <jim.bride@linux.intel.com>
> > >
> > > For DP compliance we need to be able to control the output color
> > > type for the pipe associated with the DP port. To do this we rely
> > > on the intel_dp_test_force_bpc debugfs file and the associated value
> > > stored in struct intel_dp. If the debugfs file has a non-zero value
> > > and we're on a display port connector, then we use the value from
> > > debugfs to calculate the bpp for the pipe.  For cases where we are
> > > not on DP or there has not been an overridden value then we behave
> > > as normal.
> > >
> > > Signed-off-by: Jim Bride <jim.bride@linux.intel.com>
> > > Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/intel_display.c | 32 ++++++++++++++++++++++++++++++--
> > >  drivers/gpu/drm/i915/intel_drv.h     |  1 +
> > >  2 files changed, 31 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/i915/intel_display.c
> > > b/drivers/gpu/drm/i915/intel_display.c
> > > index 5ffccf6..1618d36 100644
> > > --- a/drivers/gpu/drm/i915/intel_display.c
> > > +++ b/drivers/gpu/drm/i915/intel_display.c
> > > @@ -12102,11 +12102,39 @@ compute_baseline_pipe_bpp(struct intel_crtc *crtc,
> > >
> > >   /* Clamp display bpp to EDID value */
> > >   for_each_connector_in_state(state, connector, connector_state, i) {
> > > + int type = 0;
> > > +
> > > + if (connector_state->best_encoder) {
> > > + struct intel_encoder *ienc;
> > > +
> > > + ienc = to_intel_encoder(connector_state-
> > > >best_encoder);
> > > + type = ienc->type;
> > > + }
> > > +
> > >   if (connector_state->crtc != &crtc->base)
> > >   continue;
> > >
> > > - connected_sink_compute_bpp(to_intel_connector(connector),
> > > -    pipe_config);
> > > + /* For DP compliance we need to ensure that we can override
> > > +  * the computed bpp for the pipe.
> > > +  */
> > > + if (type == INTEL_OUTPUT_DISPLAYPORT) {
> > > + struct intel_dp *intel_dp =
> > > + enc_to_intel_dp(connector_state-
> > > >best_encoder);
> > > +
> > > + if (intel_dp &&
> > > +     (intel_dp->compliance_force_bpc != 0)) {
> > > + pipe_config->pipe_bpp =
> > > + intel_dp->compliance_force_bpc*3;
> > > + DRM_DEBUG_KMS("JMB Setting pipe_bpp to %d\n",
> > > +       pipe_config->pipe_bpp);
> > > + } else {
> > > + connected_sink_compute_bpp(to_intel_connector
> > > (connector),
> > > +    pipe_config);
> >
> > This kind of thing should be done in the encoder compute_config hook.
>
> Even though it's really not specific to an individual encoder configuration?
> This seems to be the central place where we're ensuring that we have a sane
> value for bpp relative to the display, and thus a good place to set this
> override to make compliance happy (which needs a specific bpc value for some
> test cases rather than one that is deemed sane relative to the sink's
> capabilities.
>
> >
> > > + }
> > > + } else {
> > > + connected_sink_compute_bpp(to_intel_connector(connect
> > > or),
> > > +    pipe_config);
> > > + }
> > >   }
> > >
> > >   return bpp;
> > > diff --git a/drivers/gpu/drm/i915/intel_drv.h
> > > b/drivers/gpu/drm/i915/intel_drv.h
> > > index e23eed7..10eaff8 100644
> > > --- a/drivers/gpu/drm/i915/intel_drv.h
> > > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > > @@ -865,6 +865,7 @@ struct intel_dp {
> > >   unsigned long compliance_test_type;
> > >   unsigned long compliance_test_data;
> > >   bool compliance_test_active;
> > > + unsigned long compliance_force_bpc; /* 0 for default or bpc to use */
> >
> > There's no code for setting compliance_test_active anywhere. The commit message
> > mentions debugfs, but I didn't see anything related in the patch.

The compliance_test_active is also being set as part of the compliance
test handlers for edid and video pattern generation.
>
> It appears that Manasi forgot to include one of the patches I had sent her.
> The debugfs support code was in a separate patch.
>
> Jim

We do not need the debugfs node to set the bpc value. Instead this bpc value in
intel_dp structure is being set as a part of video_pattern_autotes.
Instead of userspace setting this value through debugfs node, the kernel is setting this directly.
I will update the commit message to remove the debugfs node setting.

Manasi
>
> >
> >
> > Ander
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