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            <b><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW --- - [HSW eDP] Response time larger than expected"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=72211#c21">Comment # 21</a>
              on <a class="bz_bug_link 
          bz_status_NEW "
   title="NEW --- - [HSW eDP] Response time larger than expected"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=72211">bug 72211</a>
              from <span class="vcard"><a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> <span class="fn">Chris Wilson</span></a>
</span></b>
        <pre>Out of interest, what happens with this gratuitous hack?

diff --git a/drivers/gpu/drm/i915/intel_display.c
b/drivers/gpu/drm/i915/intel_display.c
index c3a955b5f14b..a8296de01eca 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -10024,6 +10024,16 @@ is_crtc_connector_off(struct drm_mode_set *set)
        return false;
 }

+static bool
+intel_mode_equal(const struct drm_display_mode *a,
+                const struct drm_display_mode *b)
+{
+       if (i915.fastboot)
+               return a->htotal == b->htotal && a->vtotal == b->vtotal;
+       else
+               return drm_mode_equal(a, b);
+}
+
 static void
 intel_set_config_compute_mode_changes(struct drm_mode_set *set,
                                      struct intel_set_config *config)
@@ -10059,7 +10069,7 @@ intel_set_config_compute_mode_changes(struct
drm_mode_set *set,
        if (set->fb && (set->x != set->crtc->x || set->y != set->crtc->y))
                config->fb_changed = true;

-       if (set->mode && !drm_mode_equal(set->mode, &set->crtc->mode)) {
+       if (set->mode && !intel_mode_equal(set->mode, &set->crtc->mode)) {
                DRM_DEBUG_KMS("modes are different, full mode set\n");
                drm_mode_debug_printmodeline(&set->crtc->mode);
                drm_mode_debug_printmodeline(set->mode);</pre>
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