drm/i915: don't chnage the original mode in dp_mode_fixup

We should only frob adjusted_mode. This is in preparation of
a massive patch by Laurent Pinchart to make the mode argument
const.

After the previous two prep patches the only thing left is to clean up
things a bit. I've opted to pass in an adjust_mode param to
dp_adjust_dithering because that way we can be sure to avoid
duplicating this logic between mode_valid and mode_fixup - which was
the cause behind a dp link bw calculation bug in the past.

Also mark the mode argument of pch_panel_fitting const.

v2: Split up the mode->clock => adjusted_mode->clock change,
as suggested by Chris Wilson.

Reported-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 6 insertions, 6 deletions

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 90cb39e89e61..6538c46fe959 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -234,7 +234,7 @@ intel_dp_max_data_rate(int max_link_clock, int max_lanes)
 static bool
 intel_dp_adjust_dithering(struct intel_dp *intel_dp,
                           struct drm_display_mode *mode,
-                          struct drm_display_mode *adjusted_mode)
+                          bool adjust_mode)
 {
         int max_link_clock = intel_dp_link_clock(intel_dp_max_link_bw(intel_dp));
         int max_lanes = intel_dp_max_lane_count(intel_dp);
@@ -248,8 +248,8 @@ intel_dp_adjust_dithering(struct intel_dp *intel_dp,
                 if (mode_rate > max_rate)
                         return false;
 
-                if (adjusted_mode)
-                        adjusted_mode->private_flags
+                if (adjust_mode)
+                        mode->private_flags
                                 |= INTEL_MODE_DP_FORCE_6BPC;
 
                 return true;
@@ -272,7 +272,7 @@ intel_dp_mode_valid(struct drm_connector *connector,
                         return MODE_PANEL;
         }
 
-        if (!intel_dp_adjust_dithering(intel_dp, mode, NULL))
+        if (!intel_dp_adjust_dithering(intel_dp, mode, false))
                 return MODE_CLOCK_HIGH;
 
         if (mode->clock < 10000)
@@ -712,14 +712,14 @@ intel_dp_mode_fixup(struct drm_encoder *encoder, struct drm_display_mode *mode,
                                         mode, adjusted_mode);
         }
 
-        if (mode->flags & DRM_MODE_FLAG_DBLCLK)
+        if (adjusted_mode->flags & DRM_MODE_FLAG_DBLCLK)
                 return false;
 
         DRM_DEBUG_KMS("DP link computation with max lane count %i "
                       "max bw %02x pixel clock %iKHz\n",
                       max_lane_count, bws[max_clock], adjusted_mode->clock);
 
-        if (!intel_dp_adjust_dithering(intel_dp, adjusted_mode, adjusted_mode))
+        if (!intel_dp_adjust_dithering(intel_dp, adjusted_mode, true))
                 return false;
 
         bpp = adjusted_mode->private_flags & INTEL_MODE_DP_FORCE_6BPC ? 18 : 24;