[Intel-gfx] [PATCH] drm/i915: revert eDP bpp clamping code changes

[Paulo Zanoni]

Hi

2013/4/4 Daniel Vetter <daniel.vetter at ffwll.ch>
>
> The behaviour around handling the eDP bpp value from vbt has been
> slightly changed in
>
> commit 3600836585e3fdef0a1410d63fe5ce4015007aac
> Author: Daniel Vetter <daniel.vetter at ffwll.ch>
> Date:   Wed Mar 27 00:44:59 2013 +0100
>
>     drm/i915: convert DP autodither code to new infrastructure
>
> The old behaviour was that we used the plane's bpp (usually 24bpp) for
> computing the dp link bw, but set up the pipe with the bpp value from
> vbt if available. The takes the vbt bpp override into account even for
s/The/This/ ?

> the dp link bw configuration.
>
> On Paulo's hsw machine this resulted in a slower link clock and a
> black screen - but the mode actually /should/ fit even with the lower
> clock. Until we've cleared up simply stay bug-for-bug compatible with
> the old code.
>
> While at it, also restore a debug message lost in:
>
> commit 4e53c2e010e531b4a014692199e978482d471c7e
> Author: Daniel Vetter <daniel.vetter at ffwll.ch>
> Date:   Wed Mar 27 00:44:58 2013 +0100
>
>     drm/i915: precompute pipe bpp before touching the hw
>
> Cc: Paulo Zanoni <przanoni at gmail.com>
> Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> ---
>  drivers/gpu/drm/i915/intel_dp.c |   18 ++++++++++++++----
>  1 file changed, 14 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index c5cfec3..658d071 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -741,9 +741,6 @@ intel_dp_compute_config(struct intel_encoder *encoder,
>         /* Walk through all bpp values. Luckily they're all nicely spaced with 2
>          * bpc in between. */
>         bpp = min_t(int, 8*3, pipe_config->pipe_bpp);
> -       if (is_edp(intel_dp) && dev_priv->edp.bpp)
> -               bpp = min_t(int, bpp, dev_priv->edp.bpp);
> -
>         for (; bpp >= 6*3; bpp -= 2*3) {
>                 mode_rate = intel_dp_link_required(target_clock, bpp);
>
> @@ -781,7 +778,6 @@ found:
>         intel_dp->link_bw = bws[clock];
>         intel_dp->lane_count = lane_count;
>         adjusted_mode->clock = drm_dp_bw_code_to_link_rate(intel_dp->link_bw);
> -       pipe_config->pipe_bpp = bpp;
>         pipe_config->pixel_target_clock = target_clock;
>
>         DRM_DEBUG_KMS("DP link bw %02x lane count %d clock %d bpp %d\n",
> @@ -796,6 +792,20 @@ found:
>
>         intel_dp_set_clock(encoder, pipe_config, intel_dp->link_bw);
>
> +       /*
> +        * XXX: We have a strange regression where using the vbt edp bpp value
> +        * for the link bw computation results in black screens, the panel only
> +        * works when we do the computation at the usual 24bpp (but still
> +        * requires us to use 18bpp. Until that's fully debugged, stay

We're missing a ')' character.

Reviewed-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
Tested-by: Paulo Zanoni <paulo.r.zanoni at intel.com>

> +        * bug-for-bug compatible with the old code.
> +        */
> +       if (is_edp(intel_dp) && dev_priv->edp.bpp) {
> +               DRM_DEBUG_KMS("clamping display bpc (was %d) to eDP (%d)\n",
> +                             bpp, dev_priv->edp.bpp);
> +               bpp = min_t(int, bpp, dev_priv->edp.bpp);
> +       }
> +       pipe_config->pipe_bpp = bpp;
> +
>         return true;
>  }
>
> --
> 1.7.10.4
>



--
Paulo Zanoni