[Intel-gfx] [PATCH] drm/i915: compute the target_clock for edp directly

[Chris Wilson]

On Thu, 31 May 2012 12:03:53 +0200, Daniel Vetter <daniel at ffwll.ch> wrote:
> On Thu, May 31, 2012 at 10:49:59AM +0100, Chris Wilson wrote:
> > On Wed, 30 May 2012 15:34:20 +0200, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> > > Instead of abusing into mode->clock, because we should touch that
> > > one at all. First prep step to constify the mode argument to the
> > > intel_dp_mode_fixup function.
> > > 
> > > The next patch will stop us from modifying mode->clock.
> > > 
> > > Signed-Off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> > > ---
> > >  drivers/gpu/drm/i915/intel_display.c |   16 ++++++++--------
> > >  drivers/gpu/drm/i915/intel_dp.c      |   12 ++++++++++++
> > >  drivers/gpu/drm/i915/intel_drv.h     |    2 ++
> > >  3 files changed, 22 insertions(+), 8 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> > > index 9147894..a5d06ed 100644
> > > --- a/drivers/gpu/drm/i915/intel_display.c
> > > +++ b/drivers/gpu/drm/i915/intel_display.c
> > > @@ -4431,16 +4431,8 @@ static int ironlake_crtc_mode_set(struct drm_crtc *crtc,
> > >  	/* CPU eDP doesn't require FDI link, so just set DP M/N
> > >  	   according to current link config */
> > >  	if (is_cpu_edp) {
> > > -		target_clock = mode->clock;
> > >  		intel_edp_link_config(edp_encoder, &lane, &link_bw);
> > >  	} else {
> > > -		/* [e]DP over FDI requires target mode clock
> > > -		   instead of link clock */
> > > -		if (is_dp)
> > > -			target_clock = mode->clock;
> > > -		else
> > > -			target_clock = adjusted_mode->clock;
> > > -
> > >  		/* FDI is a binary signal running at ~2.7GHz, encoding
> > >  		 * each output octet as 10 bits. The actual frequency
> > >  		 * is stored as a divider into a 100MHz clock, and the
> > > @@ -4451,6 +4443,14 @@ static int ironlake_crtc_mode_set(struct drm_crtc *crtc,
> > >  		link_bw = intel_fdi_link_freq(dev) * MHz(100)/KHz(1)/10;
> > >  	}
> > >  
> > > +	/* [e]DP over FDI requires target mode clock instead of link clock. */
> > > +	if (edp_encoder)
> > > +		target_clock = intel_edp_target_clock(edp_encoder, mode);
> > 
> > Given the edp_encoder, we know that adjusted_mode contains either the
> > fixed_panel clock or the original clock depending on whether a fixed
> > mode was found. So the layering violation could be dropped here in
> > favour of target_clock = adjusted_mode->clok.
> 
> It's not that simple. Assuming I understand this maze correctly, we're
> dealing with 3 different clocks.
> - The dp link clock, both the old and new code store that in
>   adjusted_mode->clock at the end of intel_dp_mode_fixup.

Right, missed that adjusted_mode->clock was rewritten in dp_mode_fixup.
In fact, wouldn't that make the better export from intel_dp?
   target_clock = intel_dp_link_clock(adjusted_mode);
with a judicious adjusted_mode->private_flags |= INTEL_DP_LINK_BW_2_7/1_8?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre