[Intel-gfx] [PATCH] drm/i915: Insert i915_preliminary_hw_support variable.

[Rodrigo Vivi]

On the worst scenario, users with new hardwares and old kernel from enabling times can get black screens.
So, now on, this i915_perliminary_hw_support variable shall be used by all upcoming platforms that are still under enabling.

Although it is uncomfortable for developers use this extra variable it brings more stability for end users.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi at gmail.com>
---
 drivers/gpu/drm/i915/i915_drv.c | 13 +++++++++++++
 drivers/gpu/drm/i915/i915_drv.h |  1 +
 2 files changed, 14 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index a7837e5..41bee22 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -119,6 +119,13 @@ module_param_named(i915_enable_ppgtt, i915_enable_ppgtt, int, 0600);
 MODULE_PARM_DESC(i915_enable_ppgtt,
 		"Enable PPGTT (default: true)");
 
+unsigned int i915_preliminary_hw_support __read_mostly = 0;
+module_param_named(i915_preliminary_hw_support, i915_preliminary_hw_support, int, 0600);
+MODULE_PARM_DESC(i915_preliminary_hw_support,
+		"Enable preliminary hardware support. "
+		"Enable Haswell and ValleyView Support. "
+		"(default: false)");
+
 static struct drm_driver driver;
 extern int intel_agp_enabled;
 
@@ -827,6 +834,12 @@ i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	struct intel_device_info *intel_info =
 		(struct intel_device_info *) ent->driver_data;
 
+	if (intel_info->is_haswell || intel_info->is_valleyview)
+		if(!i915_preliminary_hw_support) {
+			DRM_ERROR("Preliminary hardware support disabled\n");
+			return -ENODEV;
+		}
+
 	/* Only bind to function 0 of the device. Early generations
 	 * used function 1 as a placeholder for multi-head. This causes
 	 * us confusion instead, especially on the systems where both
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 9e446b6..5617881 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1225,6 +1225,7 @@ extern int i915_enable_rc6 __read_mostly;
 extern int i915_enable_fbc __read_mostly;
 extern bool i915_enable_hangcheck __read_mostly;
 extern int i915_enable_ppgtt __read_mostly;
+extern unsigned int i915_preliminary_hw_support __read_mostly;
 
 extern int i915_suspend(struct drm_device *dev, pm_message_t state);
 extern int i915_resume(struct drm_device *dev);
-- 
1.7.11.4