vfio/display: delay link up event

Kick the display link up event with a 0.1 sec delay,
so the guest has a chance to notice the link down first.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
[update for redefined macro]
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

2 files changed, 26 insertions, 5 deletions

diff --git a/hw/vfio/display.c b/hw/vfio/display.c
index 212ad1674e..a3d9c8f5be 100644
--- a/hw/vfio/display.c
+++ b/hw/vfio/display.c
@@ -37,6 +37,23 @@
             _reg->offset + offsetof(typeof(*_ptr), _fld)))
 
 
+static void vfio_display_edid_link_up(void *opaque)
+{
+    VFIOPCIDevice *vdev = opaque;
+    VFIODisplay *dpy = vdev->dpy;
+    int fd = vdev->vbasedev.fd;
+
+    dpy->edid_regs->link_state = VFIO_DEVICE_GFX_LINK_STATE_UP;
+    if (pwrite_field(fd, dpy->edid_info, dpy->edid_regs, link_state)) {
+        goto err;
+    }
+    trace_vfio_display_edid_link_up();
+    return;
+
+err:
+    trace_vfio_display_edid_write_error();
+}
+
 static void vfio_display_edid_update(VFIOPCIDevice *vdev, bool enabled,
                                      int prefx, int prefy)
 {
@@ -49,6 +66,7 @@ static void vfio_display_edid_update(VFIOPCIDevice *vdev, bool enabled,
         .prefy = prefy ?: vdev->display_yres,
     };
 
+    timer_del(dpy->edid_link_timer);
     dpy->edid_regs->link_state = VFIO_DEVICE_GFX_LINK_STATE_DOWN;
     if (pwrite_field(fd, dpy->edid_info, dpy->edid_regs, link_state)) {
         goto err;
@@ -80,11 +98,8 @@ static void vfio_display_edid_update(VFIOPCIDevice *vdev, bool enabled,
         goto err;
     }
 
-    dpy->edid_regs->link_state = VFIO_DEVICE_GFX_LINK_STATE_UP;
-    if (pwrite_field(fd, dpy->edid_info, dpy->edid_regs, link_state)) {
-        goto err;
-    }
-    trace_vfio_display_edid_link_up();
+    timer_mod(dpy->edid_link_timer,
+              qemu_clock_get_ms(QEMU_CLOCK_REALTIME) + 100);
     return;
 
 err:
@@ -150,6 +165,9 @@ static void vfio_display_edid_init(VFIOPCIDevice *vdev)
         vdev->display_yres = dpy->edid_regs->max_yres;
     }
 
+    dpy->edid_link_timer = timer_new_ms(QEMU_CLOCK_REALTIME,
+                                        vfio_display_edid_link_up, vdev);
+
     vfio_display_edid_update(vdev, true, 0, 0);
     return;
 
@@ -168,6 +186,8 @@ static void vfio_display_edid_exit(VFIODisplay *dpy)
 
     g_free(dpy->edid_regs);
     g_free(dpy->edid_blob);
+    timer_del(dpy->edid_link_timer);
+    timer_free(dpy->edid_link_timer);
 }
 
 static void vfio_display_update_cursor(VFIODMABuf *dmabuf,
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index 5f7f709b95..b65a2f0518 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -151,6 +151,7 @@ typedef struct VFIODisplay {
     struct vfio_region_info *edid_info;
     struct vfio_region_gfx_edid *edid_regs;
     uint8_t *edid_blob;
+    QEMUTimer *edid_link_timer;
     struct {
         VFIORegion buffer;
         DisplaySurface *surface;