drm/i915: Factor in pixel-repeat in FDI M/N calculation

Fixes the modesetting on the secondary panel of the Libretto W100 and
presumably many more Ironlake laptops with SDVO LVDS displays.

Reported-and-tested-by: Matthew Willoughby <mattfredwill@gmail.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index fac118b..d9b7092 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -3710,6 +3710,7 @@ static int intel_crtc_mode_set(struct drm_crtc *crtc,
 
        /* FDI link */
        if (HAS_PCH_SPLIT(dev)) {
+               int pixel_multiplier = intel_mode_get_pixel_multiplier(adjusted_mode);
                int lane = 0, link_bw, bpp;
                /* CPU eDP doesn't require FDI link, so just set DP M/N
                   according to current link config */
@@ -3793,6 +3794,8 @@ static int intel_crtc_mode_set(struct drm_crtc *crtc,
 
                intel_crtc->fdi_lanes = lane;
 
+               if (pixel_multiplier > 1)
+                       link_bw *= pixel_multiplier;
                ironlake_compute_m_n(bpp, lane, target_clock, link_bw, &m_n);
        }