linux-vfio/1002-i915-vga-arbiter.patch

From 33d2dbe323583bb2f344c857a100f1116fad70d9 Mon Sep 17 00:00:00 2001
From: xiota <>
Date: Fri, 29-Dec-2023 12:34:56 +0000
Subject: [PATCH 2/2] i915-vga-arbiter

---
 .../drm/i915/display/intel_display_driver.c   | 16 ++++++++--
 .../drm/i915/display/intel_display_driver.h   |  1 +
 drivers/gpu/drm/i915/display/intel_vga.c      | 31 +++++++++++++++++++
 drivers/gpu/drm/i915/display/intel_vga.h      |  4 +++
 drivers/gpu/drm/i915/i915_params.c            |  3 ++
 drivers/gpu/drm/i915/i915_params.h            |  1 +
 6 files changed, 53 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display_driver.c b/drivers/gpu/drm/i915/display/intel_display_driver.c
index 8f144d4d3..915a5ec47 100644
--- a/drivers/gpu/drm/i915/display/intel_display_driver.c
+++ b/drivers/gpu/drm/i915/display/intel_display_driver.c
@@ -205,9 +205,11 @@ int intel_display_driver_probe_noirq(struct drm_i915_private *i915)
 
 	intel_bios_init(i915);
 
-	ret = intel_vga_register(i915);
-	if (ret)
-		goto cleanup_bios;
+	if (!i915_modparams.enable_hd_vgaarb || !HAS_PCH_SPLIT(i915)) {
+		ret = intel_vga_register(i915);
+		if (ret)
+			goto cleanup_bios;
+	}
 
 	/* FIXME: completely on the wrong abstraction layer */
 	ret = intel_power_domains_init(i915);
@@ -366,6 +368,12 @@ int intel_display_driver_probe(struct drm_i915_private *i915)
 	if (ret)
 		return ret;
 
+	/*
+	 * Must do this after fbcon init so that
+	 * vgacon_save_screen() works during the handover.
+	 */
+	intel_vga_disable_mem(i915);
+
 	/* Only enable hotplug handling once the fbdev is fully set up. */
 	intel_hpd_init(i915);
 	intel_hpd_poll_disable(i915);
@@ -412,6 +420,7 @@ void intel_display_driver_remove(struct drm_i915_private *i915)
 	if (!HAS_DISPLAY(i915))
 		return;
 
+	intel_vga_enable_mem(i915);
 	flush_workqueue(i915->display.wq.flip);
 	flush_workqueue(i915->display.wq.modeset);
 
@@ -444,6 +453,7 @@ void intel_display_driver_remove_noirq(struct drm_i915_private *i915)
 	intel_unregister_dsm_handler();
 
 	/* flush any delayed tasks or pending work */
+	intel_vga_enable_mem(i915);
 	flush_workqueue(i915->unordered_wq);
 
 	intel_hdcp_component_fini(i915);
diff --git a/drivers/gpu/drm/i915/display/intel_display_driver.h b/drivers/gpu/drm/i915/display/intel_display_driver.h
index c276a58ee..54b752a93 100644
--- a/drivers/gpu/drm/i915/display/intel_display_driver.h
+++ b/drivers/gpu/drm/i915/display/intel_display_driver.h
@@ -13,6 +13,7 @@ struct drm_i915_private;
 struct drm_modeset_acquire_ctx;
 struct pci_dev;
 
+extern void intel_vga_disable_mem(struct drm_i915_private *dev_priv);
 bool intel_display_driver_probe_defer(struct pci_dev *pdev);
 void intel_display_driver_init_hw(struct drm_i915_private *i915);
 void intel_display_driver_early_probe(struct drm_i915_private *i915);
diff --git a/drivers/gpu/drm/i915/display/intel_vga.c b/drivers/gpu/drm/i915/display/intel_vga.c
index 286a0bdd2..18d30ee84 100644
--- a/drivers/gpu/drm/i915/display/intel_vga.c
+++ b/drivers/gpu/drm/i915/display/intel_vga.c
@@ -47,6 +47,36 @@ void intel_vga_disable(struct drm_i915_private *dev_priv)
 	intel_de_posting_read(dev_priv, vga_reg);
 }
 
+void intel_vga_enable_mem(struct drm_i915_private *dev_priv)
+{
+	struct pci_dev *pdev = to_pci_dev(dev_priv->drm.dev);
+
+	/* Enable VGA memory on Intel HD */
+	if (i915_modparams.enable_hd_vgaarb && HAS_PCH_SPLIT(dev_priv)) {
+		vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO);
+		outb(inb(VGA_MIS_R) | (1 << 1), VGA_MIS_W);
+		vga_set_legacy_decoding(pdev, VGA_RSRC_LEGACY_IO |
+						VGA_RSRC_LEGACY_MEM |
+						VGA_RSRC_NORMAL_IO |
+						VGA_RSRC_NORMAL_MEM);
+		vga_put(pdev, VGA_RSRC_LEGACY_IO);
+	}
+}
+
+void intel_vga_disable_mem(struct drm_i915_private *dev_priv)
+{
+	struct pci_dev *pdev = to_pci_dev(dev_priv->drm.dev);
+	/* Disable VGA memory on Intel HD */
+	if (i915_modparams.enable_hd_vgaarb && HAS_PCH_SPLIT(dev_priv)) {
+		vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO);
+		outb(inb(VGA_MIS_R) & ~(1 << 1), VGA_MIS_W);
+		vga_set_legacy_decoding(pdev, VGA_RSRC_LEGACY_IO |
+						   VGA_RSRC_NORMAL_IO |
+						   VGA_RSRC_NORMAL_MEM);
+		vga_put(pdev, VGA_RSRC_LEGACY_IO);
+	}
+}
+
 void intel_vga_redisable_power_on(struct drm_i915_private *dev_priv)
 {
 	i915_reg_t vga_reg = intel_vga_cntrl_reg(dev_priv);
@@ -55,6 +85,7 @@ void intel_vga_redisable_power_on(struct drm_i915_private *dev_priv)
 		drm_dbg_kms(&dev_priv->drm,
 			    "Something enabled VGA plane, disabling it\n");
 		intel_vga_disable(dev_priv);
+		intel_vga_disable_mem(dev_priv);
 	}
 }
 
diff --git a/drivers/gpu/drm/i915/display/intel_vga.h b/drivers/gpu/drm/i915/display/intel_vga.h
index ba5b55b91..7e2af7924 100644
--- a/drivers/gpu/drm/i915/display/intel_vga.h
+++ b/drivers/gpu/drm/i915/display/intel_vga.h
@@ -15,4 +15,8 @@ void intel_vga_redisable_power_on(struct drm_i915_private *i915);
 int intel_vga_register(struct drm_i915_private *i915);
 void intel_vga_unregister(struct drm_i915_private *i915);
 
+/* i915 vga arb patch */
+void intel_vga_enable_mem(struct drm_i915_private *i915);
+void intel_vga_disable_mem(struct drm_i915_private *i915);
+
 #endif /* __INTEL_VGA_H__ */
diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
index 0a171b57f..739d31067 100644
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -160,6 +160,9 @@ i915_param_named_unsafe(invert_brightness, int, 0400,
 i915_param_named(disable_display, bool, 0400,
 	"Disable display (default: false)");
 
+i915_param_named(enable_hd_vgaarb, bool, 0444,
+	"Enable support for VGA arbitration on Intel HD IGD. (default: false)");
+
 i915_param_named(memtest, bool, 0400,
 	"Perform a read/write test of all device memory on module load (default: off)");
 
diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h
index 68abf0ad6..507d29c52 100644
--- a/drivers/gpu/drm/i915/i915_params.h
+++ b/drivers/gpu/drm/i915/i915_params.h
@@ -79,6 +79,7 @@ struct drm_printer;
 	param(unsigned int, lmem_size, 0, 0400) \
 	param(unsigned int, lmem_bar_size, 0, 0400) \
 	/* leave bools at the end to not create holes */ \
+	param(bool, enable_hd_vgaarb, false, 0600) \
 	param(bool, enable_hangcheck, true, 0600) \
 	param(bool, load_detect_test, false, 0600) \
 	param(bool, force_reset_modeset_test, false, 0600) \
-- 
2.43.0