drm/i915: Tune down init error message due to failure injection

Atm, in case failure injection forces an error the subsequent "*ERROR*
failed to init modeset" error message will make automated tests (CI)
report this event as a breakage even though the event is expected. To
fix this print the error message with debug log level in this case.

While at it print the error message for any init failure and change it
to
"""
Device initialization failed (errno)
Please file a bug at https://bugs.freedesktop.org/enter_bug.cgi?product=DRI
against DRM/Intel providing the dmesg log by booting with drm.debug=0xf
"""
and export a helper printing error messages using this same format.
A follow-up patch will convert all uses of DRM_ERROR reporting a user
facing problem to use this new helper instead.

v2:
- Include the problematic error message in the commit log, add a
  request to file an fdo bug to the message (Chris)
v3:
- Include the new error message too in the commit log, make the
  fdo link more precise and print part of the message with info log
  level (Chris)
v4: (Chris)
- Use dev_printk instead of DRM_ERROR/INFO and use NOTICE instead of
  INFO loglevel
- Export a helper for printing user facing error messages
v5:
- Keep the DRM_ERROR message prefix used by piglit-igt/CI to filter
  relevant dmesg lines
- Use dev_notice(), instead of dev_printk(KERN_NOTICE,...)
v6:
- Print the fdo bug link only once (Chris)

CC: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1458290770-15480-1-git-send-email-imre.deak@intel.com

drivers/gpu/drm/i915/i915_dma.c

@@ -66,6 +66,47 @@ bool __i915_inject_load_failure(const char *func, int line)
 	return false;
 }
 
+#define FDO_BUG_URL "https://bugs.freedesktop.org/enter_bug.cgi?product=DRI"
+#define FDO_BUG_MSG "Please file a bug at " FDO_BUG_URL " against DRM/Intel " \
+		    "providing the dmesg log by booting with drm.debug=0xf"
+
+void
+__i915_printk(struct drm_i915_private *dev_priv, const char *level,
+	      const char *fmt, ...)
+{
+	static bool shown_bug_once;
+	struct device *dev = dev_priv->dev->dev;
+	bool is_error = level[1] <= KERN_ERR[1];
+	struct va_format vaf;
+	va_list args;
+
+	va_start(args, fmt);
+
+	vaf.fmt = fmt;
+	vaf.va = &args;
+
+	dev_printk(level, dev, "[" DRM_NAME ":%ps] %pV",
+		   __builtin_return_address(0), &vaf);
+
+	if (is_error && !shown_bug_once) {
+		dev_notice(dev, "%s", FDO_BUG_MSG);
+		shown_bug_once = true;
+	}
+
+	va_end(args);
+}
+
+static bool i915_error_injected(struct drm_i915_private *dev_priv)
+{
+	return i915.inject_load_failure &&
+	       i915_load_fail_count == i915.inject_load_failure;
+}
+
+#define i915_load_error(dev_priv, fmt, ...)				     \
+	__i915_printk(dev_priv,						     \
+		      i915_error_injected(dev_priv) ? KERN_DEBUG : KERN_ERR, \
+		      fmt, ##__VA_ARGS__)
+
 static int i915_getparam(struct drm_device *dev, void *data,
 			 struct drm_file *file_priv)
 {
@@ -972,8 +1013,6 @@ static int i915_driver_init_early(struct drm_i915_private *dev_priv,
 	if (i915_inject_load_failure())
 		return -ENODEV;
 
-	dev_priv->dev = dev;
-
 	/* Setup the write-once "constant" device info */
 	device_info = (struct intel_device_info *)&dev_priv->info;
 	memcpy(device_info, info, sizeof(dev_priv->info));
@@ -1303,6 +1342,8 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 		return -ENOMEM;
 
 	dev->dev_private = dev_priv;
+	/* Must be set before calling __i915_printk */
+	dev_priv->dev = dev;
 
 	ret = i915_driver_init_early(dev_priv, dev,
 				     (struct intel_device_info *)flags);
@@ -1332,10 +1373,8 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 	}
 
 	ret = i915_load_modeset_init(dev);
-	if (ret < 0) {
-		DRM_ERROR("failed to init modeset\n");
+	if (ret < 0)
 		goto out_cleanup_vblank;
-	}
 
 	i915_driver_register(dev_priv);
 
@@ -1357,6 +1396,8 @@ out_runtime_pm_put:
 out_free_priv:
 	kfree(dev_priv);
 
+	i915_load_error(dev_priv, "Device initialization failed (%d)\n", ret);
+
 	return ret;
 }
 

drivers/gpu/drm/i915/i915_drv.h

@@ -2696,6 +2696,13 @@ extern int i915_suspend_switcheroo(struct drm_device *dev, pm_message_t state);
 extern int i915_resume_switcheroo(struct drm_device *dev);
 
 /* i915_dma.c */
+void __printf(3, 4)
+__i915_printk(struct drm_i915_private *dev_priv, const char *level,
+	      const char *fmt, ...);
+
+#define i915_report_error(dev_priv, fmt, ...)				   \
+	__i915_printk(dev_priv, KERN_ERR, fmt, ##__VA_ARGS__)
+
 extern int i915_driver_load(struct drm_device *, unsigned long flags);
 extern int i915_driver_unload(struct drm_device *);
 extern int i915_driver_open(struct drm_device *dev, struct drm_file *file);