drm/i915: Fix DPT suspend/resume on !HAS_DISPLAY platforms

The drm.mode_config state is not initialized in case of !HAS_DISPLAY
so taking the fb_lock and iterating the fb list won't work on those
platforms. Skip the suspend/resume with an explicit check for this.

Fixes: 9755f055f512 ("drm/i915: Restore memory mapping for DPT FBs across system suspend/resume")
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211125171603.1775179-1-imre.deak@intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_dpt.c b/drivers/gpu/drm/i915/display/intel_dpt.c
index 5675578..963ca71 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dpt.c
+++ b/drivers/gpu/drm/i915/display/intel_dpt.c
@@ -183,6 +183,9 @@ void intel_dpt_resume(struct drm_i915_private *i915)
 {
        struct drm_framebuffer *drm_fb;
 
+       if (!HAS_DISPLAY(i915))
+               return;
+
        mutex_lock(&i915->drm.mode_config.fb_lock);
        drm_for_each_fb(drm_fb, &i915->drm) {
                struct intel_framebuffer *fb = to_intel_framebuffer(drm_fb);
@@ -207,6 +210,9 @@ void intel_dpt_suspend(struct drm_i915_private *i915)
 {
        struct drm_framebuffer *drm_fb;
 
+       if (!HAS_DISPLAY(i915))
+               return;
+
        mutex_lock(&i915->drm.mode_config.fb_lock);
 
        drm_for_each_fb(drm_fb, &i915->drm) {