From a27e56996687e79416d69a7e6dc26f9d8fe06059 Mon Sep 17 00:00:00 2001
From: Lucas Stach <dev@lynxeye.de>
Date: Wed, 28 Aug 2013 02:00:50 +0200
Subject: [PATCH] drm/nouveau: use MSI interrupts

MSIs were only problematic on some old, broken chipsets. But now that we
already see systems where PCI legacy interrupts are somewhat flaky, it's
really time to move to MSIs.

v2 (Ben Skeggs): blacklist BR02 boards

Signed-off-by: Lucas Stach <dev@lynxeye.de>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
---
 .../gpu/drm/nouveau/core/include/subdev/mc.h  |  1 +
 drivers/gpu/drm/nouveau/core/os.h             |  1 +
 drivers/gpu/drm/nouveau/core/subdev/mc/base.c | 24 ++++++++++++++++++-
 3 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/core/include/subdev/mc.h b/drivers/gpu/drm/nouveau/core/include/subdev/mc.h
index 9d2cd2006250..ce6569f365a7 100644
--- a/drivers/gpu/drm/nouveau/core/include/subdev/mc.h
+++ b/drivers/gpu/drm/nouveau/core/include/subdev/mc.h
@@ -12,6 +12,7 @@ struct nouveau_mc_intr {
 struct nouveau_mc {
 	struct nouveau_subdev base;
 	const struct nouveau_mc_intr *intr_map;
+	bool use_msi;
 };
 
 static inline struct nouveau_mc *
diff --git a/drivers/gpu/drm/nouveau/core/os.h b/drivers/gpu/drm/nouveau/core/os.h
index d48683a82585..191e739f30d1 100644
--- a/drivers/gpu/drm/nouveau/core/os.h
+++ b/drivers/gpu/drm/nouveau/core/os.h
@@ -19,6 +19,7 @@
 #include <linux/reboot.h>
 #include <linux/interrupt.h>
 #include <linux/log2.h>
+#include <linux/pm_runtime.h>
 
 #include <asm/unaligned.h>
 
diff --git a/drivers/gpu/drm/nouveau/core/subdev/mc/base.c b/drivers/gpu/drm/nouveau/core/subdev/mc/base.c
index 20f9a538746e..37712a6df923 100644
--- a/drivers/gpu/drm/nouveau/core/subdev/mc/base.c
+++ b/drivers/gpu/drm/nouveau/core/subdev/mc/base.c
@@ -23,7 +23,7 @@
  */
 
 #include <subdev/mc.h>
-#include <linux/pm_runtime.h>
+#include <core/option.h>
 
 static irqreturn_t
 nouveau_mc_intr(int irq, void *arg)
@@ -47,6 +47,9 @@ nouveau_mc_intr(int irq, void *arg)
 		map++;
 	}
 
+	if (pmc->use_msi)
+		nv_wr08(pmc->base.base.parent, 0x00088068, 0xff);
+
 	if (intr) {
 		nv_error(pmc, "unknown intr 0x%08x\n", stat);
 	}
@@ -81,6 +84,8 @@ _nouveau_mc_dtor(struct nouveau_object *object)
 	struct nouveau_device *device = nv_device(object);
 	struct nouveau_mc *pmc = (void *)object;
 	free_irq(device->pdev->irq, pmc);
+	if (pmc->use_msi)
+		pci_disable_msi(device->pdev);
 	nouveau_subdev_destroy(&pmc->base);
 }
 
@@ -102,6 +107,23 @@ nouveau_mc_create_(struct nouveau_object *parent, struct nouveau_object *engine,
 
 	pmc->intr_map = intr_map;
 
+	switch (device->pdev->device & 0x0ff0) {
+	case 0x00f0: /* BR02? */
+	case 0x02e0: /* BR02? */
+		pmc->use_msi = false;
+		break;
+	default:
+		pmc->use_msi = nouveau_boolopt(device->cfgopt, "NvMSI", true);
+		if (pmc->use_msi) {
+			pmc->use_msi = pci_enable_msi(device->pdev) == 0;
+			if (pmc->use_msi) {
+				nv_info(pmc, "MSI interrupts enabled\n");
+				nv_wr08(device, 0x00088068, 0xff);
+			}
+		}
+		break;
+	}
+
 	ret = request_irq(device->pdev->irq, nouveau_mc_intr,
 			  IRQF_SHARED, "nouveau", pmc);
 	if (ret < 0)
-- 
2.30.2