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, 20 insertions, 1 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
index 8a40c616b534..daf5db780956 100644
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -29,6 +29,7 @@
 #include <drm/drmP.h>
 #include <drm/drm_crtc_helper.h>
 #include <drm/radeon_drm.h>
+#include <linux/vgaarb.h>
 #include "radeon_reg.h"
 #include "radeon.h"
 #include "radeon_asic.h"
@@ -480,7 +481,18 @@ void radeon_combios_fini(struct radeon_device *rdev)
 {
 }
 
+/* if we get transitioned to only one device, tak VGA back */
+static unsigned int radeon_vga_set_decode(void *cookie, bool state)
+{
+        struct radeon_device *rdev = cookie;
 
+        radeon_vga_set_state(rdev, state);
+        if (state)
+                return VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM |
+                       VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
+        else
+                return VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
+}
 /*
  * Radeon device.
  */
@@ -578,6 +590,13 @@ int radeon_device_init(struct radeon_device *rdev,
         if (r) {
                 return r;
         }
+
+        /* if we have > 1 VGA cards, then disable the radeon VGA resources */
+        r = vga_client_register(rdev->pdev, rdev, NULL, radeon_vga_set_decode);
+        if (r) {
+                return -EINVAL;
+        }
+
         if (!rdev->new_init_path) {
                 /* Setup errata flags */
                 radeon_errata(rdev);
@@ -586,7 +605,6 @@ int radeon_device_init(struct radeon_device *rdev,
                 /* Initialize surface registers */
                 radeon_surface_init(rdev);
 
-                /* TODO: disable VGA need to use VGA request */
                 /* BIOS*/
                 if (!radeon_get_bios(rdev)) {
                         if (ASIC_IS_AVIVO(rdev))
@@ -697,6 +715,7 @@ void radeon_device_fini(struct radeon_device *rdev)
                 radeon_agp_fini(rdev);
 #endif
                 radeon_irq_kms_fini(rdev);
+                vga_client_register(rdev->pdev, NULL, NULL, NULL);
                 radeon_fence_driver_fini(rdev);
                 radeon_clocks_fini(rdev);
                 radeon_object_fini(rdev);