drm/i915/vlv: T12 eDP panel timing enforcement during reboot

The panel power sequencer on vlv doesn't appear to accept changes to its
T12 power down duration during warm reboots. This change forces a delay
for warm reboots to the T12 panel timing as defined in the VBT table for
the connected panel.

Ver2: removed redundant pr_crit(), commented magic value for pp_div_reg

Ver3: moved SYS_RESTART check earlier, new name for pp_div.

Ver4: Minor issue changes

Ver5: Move registration of reboot notifier to edp_connector_init,
      Added warning comment to handler about lack of PM notification.

Signed-off-by: Clint Taylor <clinton.a.taylor@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 52fda95..075170d 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -28,6 +28,8 @@
 #include <linux/i2c.h>
 #include <linux/slab.h>
 #include <linux/export.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
 #include <drm/drmP.h>
 #include <drm/drm_crtc.h>
 #include <drm/drm_crtc_helper.h>
@@ -336,6 +338,37 @@ static u32 _pp_stat_reg(struct intel_dp *intel_dp)
                return VLV_PIPE_PP_STATUS(vlv_power_sequencer_pipe(intel_dp));
 }
 
+/* Reboot notifier handler to shutdown panel power to guarantee T12 timing
+   This function only applicable when panel PM state is not to be tracked */
+static int edp_notify_handler(struct notifier_block *this, unsigned long code,
+                             void *unused)
+{
+       struct intel_dp *intel_dp = container_of(this, typeof(* intel_dp),
+                                                edp_notifier);
+       struct drm_device *dev = intel_dp_to_dev(intel_dp);
+       struct drm_i915_private *dev_priv = dev->dev_private;
+       u32 pp_div;
+       u32 pp_ctrl_reg, pp_div_reg;
+       enum pipe pipe = vlv_power_sequencer_pipe(intel_dp);
+
+       if (!is_edp(intel_dp) || code != SYS_RESTART)
+               return 0;
+
+       if (IS_VALLEYVIEW(dev)) {
+               pp_ctrl_reg = VLV_PIPE_PP_CONTROL(pipe);
+               pp_div_reg  = VLV_PIPE_PP_DIVISOR(pipe);
+               pp_div = I915_READ(pp_div_reg);
+               pp_div &= PP_REFERENCE_DIVIDER_MASK;
+
+               /* 0x1F write to PP_DIV_REG sets max cycle delay */
+               I915_WRITE(pp_div_reg, pp_div | 0x1F);
+               I915_WRITE(pp_ctrl_reg, PANEL_UNLOCK_REGS | PANEL_POWER_OFF);
+               msleep(intel_dp->panel_power_cycle_delay);
+       }
+
+       return 0;
+}
+
 static bool edp_have_panel_power(struct intel_dp *intel_dp)
 {
        struct drm_device *dev = intel_dp_to_dev(intel_dp);
@@ -3707,6 +3740,10 @@ void intel_dp_encoder_destroy(struct drm_encoder *encoder)
                drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
                edp_panel_vdd_off_sync(intel_dp);
                drm_modeset_unlock(&dev->mode_config.connection_mutex);
+               if (intel_dp->edp_notifier.notifier_call) {
+                       unregister_reboot_notifier(&intel_dp->edp_notifier);
+                       intel_dp->edp_notifier.notifier_call = NULL;
+               }
        }
        kfree(intel_dig_port);
 }
@@ -4184,6 +4221,11 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
        }
        mutex_unlock(&dev->mode_config.mutex);
 
+       if (IS_VALLEYVIEW(dev)) {
+               intel_dp->edp_notifier.notifier_call = edp_notify_handler;
+               register_reboot_notifier(&intel_dp->edp_notifier);
+       }
+
        intel_panel_init(&intel_connector->panel, fixed_mode, downclock_mode);
        intel_panel_setup_backlight(connector);
 

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index eaa27ee..f67340e 100644 (file)
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -538,6 +538,8 @@ struct intel_dp {
        unsigned long last_power_on;
        unsigned long last_backlight_off;
        bool psr_setup_done;
+       struct notifier_block edp_notifier;
+
        bool use_tps3;
        struct intel_connector *attached_connector;