linux-vfio/1002-6.13.0-i915-vga-arbiter.patch

From 32d421bf11726bac8f1bbf105095db02023117d5 Mon Sep 17 00:00:00 2001
From: xiota <>
Date: Mon, 27 Jan 2025 05:45:27 +0000
Subject: [PATCH] i915-vga-arbiter

---
 .../drm/i915/display/intel_display_driver.c   | 20 +++++++++--
 .../drm/i915/display/intel_display_driver.h   |  1 +
 .../drm/i915/display/intel_display_params.c   |  3 ++
 .../drm/i915/display/intel_display_params.h   |  1 +
 drivers/gpu/drm/i915/display/intel_vga.c      | 33 +++++++++++++++++++
 drivers/gpu/drm/i915/display/intel_vga.h      |  4 +++
 .../gpu/drm/xe/compat-i915-headers/i915_drv.h |  7 ++++
 7 files changed, 66 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 56b78cf6b..b787f82dc 100644
--- a/drivers/gpu/drm/i915/display/intel_display_driver.c
+++ b/drivers/gpu/drm/i915/display/intel_display_driver.c
@@ -30,6 +30,7 @@
 #include "intel_display_debugfs.h"
 #include "intel_display_driver.h"
 #include "intel_display_irq.h"
+#include "intel_display_params.h"
 #include "intel_display_power.h"
 #include "intel_display_types.h"
 #include "intel_display_wa.h"
@@ -221,9 +222,11 @@ int intel_display_driver_probe_noirq(struct drm_i915_private *i915)
 
 	intel_bios_init(display);
 
-	ret = intel_vga_register(display);
-	if (ret)
-		goto cleanup_bios;
+	if (!display->params.enable_hd_vgaarb || !HAS_PCH_SPLIT(i915)) {
+		ret = intel_vga_register(display);
+		if (ret)
+			goto cleanup_bios;
+	}
 
 	/* FIXME: completely on the wrong abstraction layer */
 	ret = intel_power_domains_init(i915);
@@ -520,6 +523,12 @@ int intel_display_driver_probe(struct drm_i915_private *i915)
 
 	intel_overlay_setup(i915);
 
+	/*
+	 * Must do this after fbcon init so that
+	 * vgacon_save_screen() works during the handover.
+	 */
+	intel_vga_disable_mem(display);
+
 	/* Only enable hotplug handling once the fbdev is fully set up. */
 	intel_hpd_init(i915);
 
@@ -566,9 +575,13 @@ void intel_display_driver_register(struct drm_i915_private *i915)
 /* part #1: call before irq uninstall */
 void intel_display_driver_remove(struct drm_i915_private *i915)
 {
+	struct intel_display *display = &i915->display;
+
 	if (!HAS_DISPLAY(i915))
 		return;
 
+	intel_vga_enable_mem(display);
+
 	flush_workqueue(i915->display.wq.flip);
 	flush_workqueue(i915->display.wq.modeset);
 
@@ -599,6 +612,7 @@ 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(display);
 	flush_workqueue(i915->unordered_wq);
 
 	intel_hdcp_component_fini(display);
diff --git a/drivers/gpu/drm/i915/display/intel_display_driver.h b/drivers/gpu/drm/i915/display/intel_display_driver.h
index 42cc4af6d..3b233969b 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 intel_display *display);
 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_display_params.c b/drivers/gpu/drm/i915/display/intel_display_params.c
index 024de8abc..efc57e90c 100644
--- a/drivers/gpu/drm/i915/display/intel_display_params.c
+++ b/drivers/gpu/drm/i915/display/intel_display_params.c
@@ -94,6 +94,9 @@ intel_display_param_named_unsafe(force_reset_modeset_test, bool, 0400,
 intel_display_param_named(disable_display, bool, 0400,
 	"Disable display (default: false)");
 
+intel_display_param_named(enable_hd_vgaarb, bool, 0400,
+	"Enable support for VGA arbitration on Intel HD IGD. (default: false)");
+
 intel_display_param_named(verbose_state_checks, bool, 0400,
 	"Enable verbose logs (ie. WARN_ON()) in case of unexpected hw state conditions.");
 
diff --git a/drivers/gpu/drm/i915/display/intel_display_params.h b/drivers/gpu/drm/i915/display/intel_display_params.h
index dcb6face9..1900b9ff9 100644
--- a/drivers/gpu/drm/i915/display/intel_display_params.h
+++ b/drivers/gpu/drm/i915/display/intel_display_params.h
@@ -40,6 +40,7 @@ struct drm_printer;
 	param(bool, load_detect_test, false, 0600) \
 	param(bool, force_reset_modeset_test, false, 0600) \
 	param(bool, disable_display, false, 0400) \
+	param(bool, enable_hd_vgaarb, false, 0600) \
 	param(bool, verbose_state_checks, true, 0400) \
 	param(bool, nuclear_pageflip, false, 0400) \
 	param(bool, enable_dp_mst, true, 0600) \
diff --git a/drivers/gpu/drm/i915/display/intel_vga.c b/drivers/gpu/drm/i915/display/intel_vga.c
index fd18dd07a..a587c5bc2 100644
--- a/drivers/gpu/drm/i915/display/intel_vga.c
+++ b/drivers/gpu/drm/i915/display/intel_vga.c
@@ -12,6 +12,7 @@
 #include "i915_drv.h"
 #include "i915_reg.h"
 #include "intel_de.h"
+#include "intel_display_params.h"
 #include "intel_vga.h"
 
 static i915_reg_t intel_vga_cntrl_reg(struct intel_display *display)
@@ -46,6 +47,37 @@ void intel_vga_disable(struct intel_display *display)
 	intel_de_posting_read(display, vga_reg);
 }
 
+void intel_vga_enable_mem(struct intel_display *display)
+{
+	struct pci_dev *pdev = to_pci_dev(display->drm->dev);
+	struct drm_i915_private *i915 = pdev_to_i915(pdev);
+	/* Enable VGA memory on Intel HD */
+	if (display->params.enable_hd_vgaarb && HAS_PCH_SPLIT(i915)) {
+		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 intel_display *display)
+{
+	struct pci_dev *pdev = to_pci_dev(display->drm->dev);
+	struct drm_i915_private *i915 = pdev_to_i915(pdev);
+	/* Disable VGA memory on Intel HD */
+	if (display->params.enable_hd_vgaarb && HAS_PCH_SPLIT(i915)) {
+		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 intel_display *display)
 {
 	i915_reg_t vga_reg = intel_vga_cntrl_reg(display);
@@ -54,6 +86,7 @@ void intel_vga_redisable_power_on(struct intel_display *display)
 		drm_dbg_kms(display->drm,
 			    "Something enabled VGA plane, disabling it\n");
 		intel_vga_disable(display);
+		intel_vga_disable_mem(display);
 	}
 }
 
diff --git a/drivers/gpu/drm/i915/display/intel_vga.h b/drivers/gpu/drm/i915/display/intel_vga.h
index 824dfc32a..ebe2c89d9 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 intel_display *display);
 int intel_vga_register(struct intel_display *display);
 void intel_vga_unregister(struct intel_display *display);
 
+/* i915 vga arb patch */
+void intel_vga_enable_mem(struct intel_display *display);
+void intel_vga_disable_mem(struct intel_display *display);
+
 #endif /* __INTEL_VGA_H__ */
diff --git a/drivers/gpu/drm/xe/compat-i915-headers/i915_drv.h b/drivers/gpu/drm/xe/compat-i915-headers/i915_drv.h
index 84b0991b3..a908e706e 100644
--- a/drivers/gpu/drm/xe/compat-i915-headers/i915_drv.h
+++ b/drivers/gpu/drm/xe/compat-i915-headers/i915_drv.h
@@ -22,6 +22,13 @@ static inline struct drm_i915_private *to_i915(const struct drm_device *dev)
 	return container_of(dev, struct drm_i915_private, drm);
 }
 
+static inline struct drm_i915_private *pdev_to_i915(struct pci_dev *pdev)
+{
+	struct drm_device *drm = pci_get_drvdata(pdev);
+
+	return drm ? to_i915(drm) : NULL;
+}
+
 #define IS_PLATFORM(xe, x) ((xe)->info.platform == x)
 #define INTEL_INFO(dev_priv)	(&((dev_priv)->info))
 #define IS_I830(dev_priv)	(dev_priv && 0)
-- 
2.48.1