drm/vgaarb: add VGA arbitration support to the drm and kms.

VGA arb requires DRM support for non-kms drivers, to turn on/off
irqs when disabling the mem/io regions.

VGA arb requires KMS support for GPUs where we can turn off VGA
decoding. Currently we know how to do this for intel and radeon
kms drivers, which allows them to be removed from the arbiter.

This patch comes from Fedora rawhide kernel.

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index f85aaf2..0a6f0b3 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -37,6 +37,7 @@
 
 #include <linux/interrupt.h>	/* For task queue support */
 
+#include <linux/vgaarb.h>
 /**
  * Get interrupt from bus id.
  *
@@ -171,6 +172,26 @@ err:
 }
 EXPORT_SYMBOL(drm_vblank_init);
 
+static void drm_irq_vgaarb_nokms(void *cookie, bool state)
+{
+	struct drm_device *dev = cookie;
+
+	if (dev->driver->vgaarb_irq) {
+		dev->driver->vgaarb_irq(dev, state);
+		return;
+	}
+
+	if (!dev->irq_enabled)
+		return;
+
+	if (state)
+		dev->driver->irq_uninstall(dev);
+	else {
+		dev->driver->irq_preinstall(dev);
+		dev->driver->irq_postinstall(dev);
+	}
+}
+
 /**
  * Install IRQ handler.
  *
@@ -231,6 +252,9 @@ int drm_irq_install(struct drm_device *dev)
 		return ret;
 	}
 
+	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+		vga_client_register(dev->pdev, (void *)dev, drm_irq_vgaarb_nokms, NULL);
+
 	/* After installing handler */
 	ret = dev->driver->irq_postinstall(dev);
 	if (ret < 0) {
@@ -279,6 +303,9 @@ int drm_irq_uninstall(struct drm_device * dev)
 
 	DRM_DEBUG("irq=%d\n", dev->pdev->irq);
 
+	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+		vga_client_register(dev->pdev, NULL, NULL, NULL);
+
 	dev->driver->irq_uninstall(dev);
 
 	free_irq(dev->pdev->irq, dev);