drm/i915/dp: Boost timeout for enabling transcoder to 100ms

Adam Hill reported that his Arrandale system required a much longer, up
to 200x500us, wait for the panel to initialise or else modesetting would
fail.

References:

  https://bugs.freedesktop.org/show_bug.cgi?id=29141

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reported-and-tested-by: Adam Hill <sidepipeuk@yahoo.co.uk>

drivers/gpu/drm/i915/intel_display.c

@@ -2069,7 +2069,7 @@ static void ironlake_crtc_dpms(struct drm_crtc *crtc, int mode)
 			I915_WRITE(transconf_reg, temp | TRANS_ENABLE);
 			I915_READ(transconf_reg);
 
-			if (wait_for(I915_READ(transconf_reg) & TRANS_STATE_ENABLE, 10, 0))
+			if (wait_for(I915_READ(transconf_reg) & TRANS_STATE_ENABLE, 100, 1))
 				DRM_ERROR("failed to enable transcoder\n");
 		}