[Bug 67813] [HSW bisected]igt/module_reload causes [drm:hsw_unclaimed_reg_check] *ERROR* Unclaimed write to 44004 and system hang with headless, with power well disabled

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=67813

--- Comment #41 from Paulo Zanoni <przanoni at gmail.com> ---
This solves the problem:


diff --git a/drivers/gpu/drm/i915/intel_display.c
b/drivers/gpu/drm/i915/intel_display.c
index a28347d..ea5b3f7 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -10801,6 +10801,22 @@ static void intel_init_quirks(struct drm_device *dev)
     }
 }

+void i915_power_well_redisable_vga(struct drm_i915_private *dev_priv)
+{
+    struct drm_device *dev = dev_priv->dev;
+    u8 val;
+
+    vga_get_uninterruptible(dev->pdev, VGA_RSRC_LEGACY_IO);
+    val = inb(VGA_MSR_READ);
+    DRM_DEBUG_KMS("=== msr_read read:  0x%04x\n", val);
+    outb(val & ~VGA_MSR_MEM_EN, VGA_MSR_WRITE);
+    DRM_DEBUG_KMS("=== msr_read write: 0x%04x\n", val & ~VGA_MSR_MEM_EN);
+    vga_set_legacy_decoding(dev->pdev, VGA_RSRC_LEGACY_IO |
+                       VGA_RSRC_NORMAL_IO |
+                       VGA_RSRC_NORMAL_MEM);
+    vga_put(dev->pdev, VGA_RSRC_LEGACY_IO);
+}
+
 /* Disable the VGA plane that we never use */
 static void i915_disable_vga(struct drm_device *dev)
 {
diff --git a/drivers/gpu/drm/i915/intel_drv.h
b/drivers/gpu/drm/i915/intel_drv.h
index b5e7cb5..d7a5b13 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -705,6 +705,7 @@ void
 ironlake_check_encoder_dotclock(const struct intel_crtc_config *pipe_config,
                 int dotclock);
 bool intel_crtc_active(struct drm_crtc *crtc);
+void i915_power_well_redisable_vga(struct drm_i915_private *dev_priv);
 void i915_disable_vga_mem(struct drm_device *dev);
 void hsw_enable_ips(struct intel_crtc *crtc);
 void hsw_disable_ips(struct intel_crtc *crtc);
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 6374884..425807b 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -5694,6 +5694,8 @@ static void hsw_set_power_well(struct drm_device *dev,
             if (wait_for((I915_READ(HSW_PWR_WELL_DRIVER) &
                       HSW_PWR_WELL_STATE_ENABLED), 20))
                 DRM_ERROR("Timeout enabling power well\n");
+
+            i915_power_well_redisable_vga(dev_priv);
         }

         if (IS_BROADWELL(dev)) {


And the interesting thing, here's "dmesg | grep ===" from booting my machine
with this patch (eDP+HDMI):
[    7.201853] [drm:i915_power_well_redisable_vga], === msr_read read:  0x0000
[    7.201855] [drm:i915_power_well_redisable_vga], === msr_read write: 0x0000

So we read zero and write zero, and that seems to solve the problem....

-- 
You are receiving this mail because:
You are the QA Contact for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/intel-gfx-bugs/attachments/20131128/2513cb13/attachment-0001.html>