i195 VGA arbitration patch for 3.16.0.4 in Debian 8.2 Jessie

i915_317.patch

diff -rupN linux-3.16.7-ckt11.old/drivers/gpu/drm/i915/i915_dma.c linux-3.16.7-ckt11/drivers/gpu/drm/i915/i915_dma.c
--- linux-3.16.7-ckt11.old/drivers/gpu/drm/i915/i915_dma.c	2014-10-05 17:23:04.000000000 -0200
+++ linux-3.16.7-ckt11/drivers/gpu/drm/i915/i915_dma.c	2014-10-08 13:25:35.261920170 -0200
@@ -1316,10 +1316,20 @@ static int i915_load_modeset_init(struct
 	 * If we are a secondary display controller (!PCI_DISPLAY_CLASS_VGA),
 	 * then we do not take part in VGA arbitration and the
 	 * vga_client_register() fails with -ENODEV.
+	 *
+	 * NB.  The set_decode callback here actually only works on GMCH
+	 * devices, on newer HD devices we can only disable VGA MMIO space.
+	 * Disabling VGA I/O space requires disabling I/O in the PCI command
+	 * register.  Nonetheless, we like to pretend that we participate in
+	 * VGA arbitration and can dynamically disable VGA I/O space because
+	 * this makes X happy, even though it's a complete lie.
 	 */
-	ret = vga_client_register(dev->pdev, dev, NULL, i915_vga_set_decode);
-	if (ret && ret != -ENODEV)
-		goto out;
+	if (!i915.enable_hd_vgaarb || !HAS_PCH_SPLIT(dev)) {
+		ret = vga_client_register(dev->pdev, dev, NULL,
+					  i915_vga_set_decode);
+		if (ret && ret != -ENODEV)
+			goto out;
+	}
 
 	intel_register_dsm_handler();
 
@@ -1369,6 +1379,12 @@ static int i915_load_modeset_init(struct
 	if (ret)
 		goto cleanup_gem;
 
+	/*
+	 * Must do this after fbcon init so that
+	 * vgacon_save_screen() works during the handover.
+	 */
+	i915_disable_vga_mem(dev);
+
 	/* Only enable hotplug handling once the fbdev is fully set up. */
 	intel_hpd_init(dev);
 
diff -rupN linux-3.16.7-ckt11.old/drivers/gpu/drm/i915/i915_drv.h linux-3.16.7-ckt11/drivers/gpu/drm/i915/i915_drv.h
--- linux-3.16.7-ckt11.old/drivers/gpu/drm/i915/i915_drv.h	2014-10-05 17:23:04.000000000 -0200
+++ linux-3.16.7-ckt11/drivers/gpu/drm/i915/i915_drv.h	2014-10-08 13:26:45.200867353 -0200
@@ -2147,6 +2147,7 @@ struct i915_params {
 	bool enable_hangcheck;
 	bool fastboot;
 	bool prefault_disable;
+	bool enable_hd_vgaarb;
 	bool reset;
 	bool disable_display;
 	bool disable_vtd_wa;
diff -rupN linux-3.16.7-ckt11.old/drivers/gpu/drm/i915/i915_params.c linux-3.16.7-ckt11/drivers/gpu/drm/i915/i915_params.c
--- linux-3.16.7-ckt11.old/drivers/gpu/drm/i915/i915_params.c	2014-10-05 17:23:04.000000000 -0200
+++ linux-3.16.7-ckt11/drivers/gpu/drm/i915/i915_params.c	2014-10-08 13:28:08.960803683 -0200
@@ -48,6 +48,7 @@ struct i915_params i915 __read_mostly =
 	.prefault_disable = 0,
 	.reset = true,
 	.invert_brightness = 0,
+	.enable_hd_vgaarb = false,
 	.disable_display = 0,
 	.enable_cmd_parser = 1,
 	.disable_vtd_wa = 0,
@@ -159,6 +160,10 @@ module_param_named(enable_cmd_parser, i9
 module_param_named(disable_vtd_wa, i915.disable_vtd_wa, bool, 0600);
 MODULE_PARM_DESC(disable_vtd_wa, "Disable all VT-d workarounds (default: false)");
 
+module_param_named(enable_hd_vgaarb, i915.enable_hd_vgaarb, bool, 0444);
+MODULE_PARM_DESC(enable_hd_vgaarb,
+	"Enable support for VGA arbitration on Intel HD IGD. (default: false)");
+
 module_param_named(enable_cmd_parser, i915.enable_cmd_parser, int, 0600);
 MODULE_PARM_DESC(enable_cmd_parser,
 		 "Enable command parsing (1=enabled [default], 0=disabled)");
diff -rupN linux-3.16.7-ckt11.old/drivers/gpu/drm/i915/intel_display.c linux-3.16.7-ckt11/drivers/gpu/drm/i915/intel_display.c
--- linux-3.16.7-ckt11.old/drivers/gpu/drm/i915/intel_display.c	2014-10-05 17:23:04.000000000 -0200
+++ linux-3.16.7-ckt11/drivers/gpu/drm/i915/intel_display.c	2014-10-08 13:25:35.416920053 -0200
@@ -12554,6 +12554,33 @@ static void i915_disable_vga(struct drm_
 	POSTING_READ(vga_reg);
 }
 
+static void i915_enable_vga_mem(struct drm_device *dev)
+{
+	/* Enable VGA memory on Intel HD */
+	if (i915.enable_hd_vgaarb && HAS_PCH_SPLIT(dev)) {
+		vga_get_uninterruptible(dev->pdev, VGA_RSRC_LEGACY_IO);
+		outb(inb(VGA_MSR_READ) | VGA_MSR_MEM_EN, VGA_MSR_WRITE);
+		vga_set_legacy_decoding(dev->pdev, VGA_RSRC_LEGACY_IO |
+						   VGA_RSRC_LEGACY_MEM |
+						   VGA_RSRC_NORMAL_IO |
+						   VGA_RSRC_NORMAL_MEM);
+		vga_put(dev->pdev, VGA_RSRC_LEGACY_IO);
+	}
+}
+
+void i915_disable_vga_mem(struct drm_device *dev)
+{
+	/* Disable VGA memory on Intel HD */
+	if (i915.enable_hd_vgaarb && HAS_PCH_SPLIT(dev)) {
+		vga_get_uninterruptible(dev->pdev, VGA_RSRC_LEGACY_IO);
+		outb(inb(VGA_MSR_READ) & ~VGA_MSR_MEM_EN, VGA_MSR_WRITE);
+		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);
+	}
+}
+
 void intel_modeset_init_hw(struct drm_device *dev)
 {
 	intel_prepare_ddi(dev);
@@ -12891,6 +12918,7 @@ void i915_redisable_vga_power_on(struct
 	if (!(I915_READ(vga_reg) & VGA_DISP_DISABLE)) {
 		DRM_DEBUG_KMS("Something enabled VGA plane, disabling it\n");
 		i915_disable_vga(dev);
+		i915_disable_vga_mem(dev);
 	}
 }
 
@@ -13144,6 +13172,8 @@ void intel_modeset_cleanup(struct drm_de
 
 	intel_disable_fbc(dev);
 
+	i915_enable_vga_mem(dev);
+
 	intel_disable_gt_powersave(dev);
 
 	ironlake_teardown_rc6(dev);
diff -rupN linux-3.16.7-ckt11.old/drivers/gpu/drm/i915/intel_drv.h linux-3.16.7-ckt11/drivers/gpu/drm/i915/intel_drv.h
--- linux-3.16.7-ckt11.old/drivers/gpu/drm/i915/intel_drv.h	2014-10-05 17:23:04.000000000 -0200
+++ linux-3.16.7-ckt11/drivers/gpu/drm/i915/intel_drv.h	2014-10-08 13:25:35.416920053 -0200
@@ -1102,4 +1102,6 @@ int intel_sprite_get_colorkey(struct drm
 /* intel_tv.c */
 void intel_tv_init(struct drm_device *dev);
 
+extern void i915_disable_vga_mem(struct drm_device *dev);
+
 #endif /* __INTEL_DRV_H__ */
diff -rupN linux-3.16.7-ckt11.old/include/linux/vgaarb.h linux-3.16.7-ckt11/include/linux/vgaarb.h
--- linux-3.16.7-ckt11.old/include/linux/vgaarb.h	2014-10-05 17:23:04.000000000 -0200
+++ linux-3.16.7-ckt11/include/linux/vgaarb.h	2014-10-08 13:25:35.426920046 -0200
@@ -65,8 +65,15 @@ struct pci_dev;
  *     out of the arbitration process (and can be safe to take
  *     interrupts at any time.
  */
+#if defined(CONFIG_VGA_ARB)
 extern void vga_set_legacy_decoding(struct pci_dev *pdev,
 				    unsigned int decodes);
+#else
+static inline void vga_set_legacy_decoding(struct pci_dev *pdev,
+					   unsigned int decodes)
+{
+}
+#endif
 
 /**
  *     vga_get         - acquire & locks VGA resources