linux-vfio/0002-i915-vga-arbiter.patch

From 61009bd54ec93d15f9c26325cf5e5c68ac98becc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=A9clairevoyant?=
 <848000+eclairevoyant@users.noreply.github.com>
Date: Tue, 14 Mar 2023 17:07:40 -0400
Subject: [PATCH 2/2] i915-vga-arbiter

---
 drivers/gpu/drm/i915/display/intel_display.c | 15 ++++++++--
 drivers/gpu/drm/i915/display/intel_display.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, 52 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index dedbdb175f8b..e7e95308f6e6 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -8646,9 +8646,11 @@ int intel_modeset_init_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 */
 	intel_power_domains_init_hw(i915, false);
@@ -8796,6 +8798,12 @@ int intel_modeset_init(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);
@@ -8966,6 +8974,7 @@ void intel_modeset_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);
 
diff --git a/drivers/gpu/drm/i915/display/intel_display.h b/drivers/gpu/drm/i915/display/intel_display.h
index 714030136b7f..fbd500249ab1 100644
--- a/drivers/gpu/drm/i915/display/intel_display.h
+++ b/drivers/gpu/drm/i915/display/intel_display.h
@@ -535,6 +535,7 @@ void i830_disable_pipe(struct drm_i915_private *dev_priv, enum pipe pipe);
 int vlv_get_hpll_vco(struct drm_i915_private *dev_priv);
 int vlv_get_cck_clock(struct drm_i915_private *dev_priv,
 		      const char *name, u32 reg, int ref_freq);
+extern void intel_vga_disable_mem(struct drm_i915_private *dev_priv);
 int vlv_get_cck_clock_hpll(struct drm_i915_private *dev_priv,
 			   const char *name, u32 reg);
 void intel_init_display_hooks(struct drm_i915_private *dev_priv);
diff --git a/drivers/gpu/drm/i915/display/intel_vga.c b/drivers/gpu/drm/i915/display/intel_vga.c
index a69bfcac9a94..4cafe1f812f5 100644
--- a/drivers/gpu/drm/i915/display/intel_vga.c
+++ b/drivers/gpu/drm/i915/display/intel_vga.c
@@ -46,6 +46,36 @@ 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);
@@ -54,6 +84,7 @@ 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 ba5b55b917f0..7e2af7924e99 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 d1e4d528cb17..a00cbc6591b0 100644
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -154,6 +154,9 @@ 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 2733cb6cfe09..f21c5b1529cc 100644
--- a/drivers/gpu/drm/i915/i915_params.h
+++ b/drivers/gpu/drm/i915/i915_params.h
@@ -76,6 +76,7 @@ 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) \
-- 
2.39.2