drm/i915/skl: Restore pipe interrupt registers after power well enabling

The pipe interrupt registers are in the actual pipe power well, so we
need to restore them when re-enable the corresponding power well.

I've also copied what we do on HSW/BDW for VGA, even if the we haven't
enabled unclaimed registers just yet.

v2: Don't run skl_power_well_post_enable() if the power well is already
    enabled (Paulo)

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index d77a4b6..92e1ee4 100644 (file)
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -3175,6 +3175,10 @@ void gen8_irq_power_well_post_enable(struct drm_i915_private *dev_priv,
        uint32_t extra_ier = GEN8_PIPE_VBLANK | GEN8_PIPE_FIFO_UNDERRUN;
 
        spin_lock_irq(&dev_priv->irq_lock);
+       if (pipe_mask & 1 << PIPE_A)
+               GEN8_IRQ_INIT_NDX(DE_PIPE, PIPE_A,
+                                 dev_priv->de_irq_mask[PIPE_A],
+                                 ~dev_priv->de_irq_mask[PIPE_A] | extra_ier);
        if (pipe_mask & 1 << PIPE_B)
                GEN8_IRQ_INIT_NDX(DE_PIPE, PIPE_B,
                                  dev_priv->de_irq_mask[PIPE_B],

diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index 46ffb25..87a449c 100644 (file)
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -199,6 +199,34 @@ static void hsw_power_well_post_enable(struct drm_i915_private *dev_priv)
                                                1 << PIPE_C | 1 << PIPE_B);
 }
 
+static void skl_power_well_post_enable(struct drm_i915_private *dev_priv,
+                                      struct i915_power_well *power_well)
+{
+       struct drm_device *dev = dev_priv->dev;
+
+       /*
+        * After we re-enable the power well, if we touch VGA register 0x3d5
+        * we'll get unclaimed register interrupts. This stops after we write
+        * anything to the VGA MSR register. The vgacon module uses this
+        * register all the time, so if we unbind our driver and, as a
+        * consequence, bind vgacon, we'll get stuck in an infinite loop at
+        * console_unlock(). So make here we touch the VGA MSR register, making
+        * sure vgacon can keep working normally without triggering interrupts
+        * and error messages.
+        */
+       if (power_well->data == SKL_DISP_PW_2) {
+               vga_get_uninterruptible(dev->pdev, VGA_RSRC_LEGACY_IO);
+               outb(inb(VGA_MSR_READ), VGA_MSR_WRITE);
+               vga_put(dev->pdev, VGA_RSRC_LEGACY_IO);
+
+               gen8_irq_power_well_post_enable(dev_priv,
+                                               1 << PIPE_C | 1 << PIPE_B);
+       }
+
+       if (power_well->data == SKL_DISP_PW_1)
+               gen8_irq_power_well_post_enable(dev_priv, 1 << PIPE_A);
+}
+
 static void hsw_set_power_well(struct drm_i915_private *dev_priv,
                               struct i915_power_well *power_well, bool enable)
 {
@@ -361,6 +389,9 @@ static void skl_set_power_well(struct drm_i915_private *dev_priv,
                                DRM_ERROR("PG2 distributing status timeout\n");
                }
        }
+
+       if (enable && !is_enabled)
+               skl_power_well_post_enable(dev_priv, power_well);
 }
 
 static void hsw_power_well_sync_hw(struct drm_i915_private *dev_priv,