From ae18989eb9ea71dc93199bf0761f666a3eccaa73 Mon Sep 17 00:00:00 2001
From: Konstantin Belousov <kib@FreeBSD.org>
Date: Tue, 3 Feb 2015 10:30:41 +0000
Subject: [PATCH] Do not attach to the unsupported chipsets, unless magic
 tunable is frobbed.

Sponsored by:	The FreeBSD Foundation
---
 sys/dev/drm2/i915/i915_drv.c | 17 ++++++++++++++++-
 sys/dev/drm2/i915/i915_drv.h |  1 +
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/sys/dev/drm2/i915/i915_drv.c b/sys/dev/drm2/i915/i915_drv.c
index b5a43a54df3f..ef6a1513b2ee 100644
--- a/sys/dev/drm2/i915/i915_drv.c
+++ b/sys/dev/drm2/i915/i915_drv.c
@@ -208,6 +208,7 @@ static const struct intel_device_info intel_haswell_d_info = {
 	.has_blt_ring = 1,
 	.has_llc = 1,
 	.has_pch_split = 1,
+	.not_supported = 1,
 };
 
 static const struct intel_device_info intel_haswell_m_info = {
@@ -217,6 +218,7 @@ static const struct intel_device_info intel_haswell_m_info = {
 	.has_blt_ring = 1,
 	.has_llc = 1,
 	.has_pch_split = 1,
+	.not_supported = 1,
 };
 
 #define INTEL_VGA_DEVICE(id, info_) {		\
@@ -282,6 +284,8 @@ static const struct intel_gfx_device_id {
 	{0, 0}
 };
 
+static int i915_enable_unsupported;
+
 static int i915_drm_freeze(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv;
@@ -413,8 +417,16 @@ i915_resume(device_t kdev)
 static int
 i915_probe(device_t kdev)
 {
+	const struct intel_device_info *info;
+	int error;
 
-	return drm_probe(kdev, i915_pciidlist);
+	error = drm_probe(kdev, i915_pciidlist);
+	if (error != 0)
+		return (error);
+	info = i915_get_device_id(pci_get_device(kdev));
+	if (info == NULL)
+		return (ENXIO);
+	return (0);
 }
 
 int i915_modeset;
@@ -458,6 +470,8 @@ i915_get_device_id(int device)
 	for (did = &pciidlist[0]; did->device != 0; did++) {
 		if (did->device != device)
 			continue;
+		if (did->info->not_supported && !i915_enable_unsupported)
+			return (NULL);
 		return (did->info);
 	}
 	return (NULL);
@@ -527,6 +541,7 @@ int i915_enable_ppgtt = -1;
 TUNABLE_INT("drm.i915.enable_ppgtt", &i915_enable_ppgtt);
 int i915_enable_hangcheck = 1;
 TUNABLE_INT("drm.i915.enable_hangcheck", &i915_enable_hangcheck);
+TUNABLE_INT("drm.i915.enable_unsupported", &i915_enable_unsupported);
 
 #define	PCI_VENDOR_INTEL		0x8086
 #define INTEL_PCH_DEVICE_ID_MASK	0xff00
diff --git a/sys/dev/drm2/i915/i915_drv.h b/sys/dev/drm2/i915/i915_drv.h
index c5f85d642ee4..7e7be82cc8cb 100644
--- a/sys/dev/drm2/i915/i915_drv.h
+++ b/sys/dev/drm2/i915/i915_drv.h
@@ -166,6 +166,7 @@ struct drm_i915_display_funcs {
 
 struct intel_device_info {
 	u8 gen;
+	u8 not_supported:1;
 	u8 is_mobile:1;
 	u8 is_i85x:1;
 	u8 is_i915g:1;