Re: [Qemu-devel] [PATCH v2 3/3] vfio/display: delay link up event

[Alex Williamson <alex.williamson@redhat.com>]

On Wed, 20 Feb 2019 09:47:53 +0100
Gerd Hoffmann <kraxel@redhat.com> wrote:

> 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>
> ---
>  include/hw/vfio/vfio-common.h |  1 +
>  hw/vfio/display.c             | 26 +++++++++++++++++++++++---
>  2 files changed, 24 insertions(+), 3 deletions(-)
> 
> 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;
> diff --git a/hw/vfio/display.c b/hw/vfio/display.c
> index 7b9b604a64..361823b23b 100644
> --- a/hw/vfio/display.c
> +++ b/hw/vfio/display.c
> @@ -38,6 +38,21 @@
>          goto err;
>  
>  
> +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;
> +    pwrite_field(fd, dpy->edid_info, dpy->edid_regs, link_state);
> +    trace_vfio_display_edid_link_up();
> +    return;
> +
> +err:
> +    trace_vfio_display_edid_write_error();

No jumps to here.  Thanks,

Alex

> +}
> +
>  static void vfio_display_edid_update(VFIOPCIDevice *vdev, bool enabled,
>                                       int prefx, int prefy)
>  {
> @@ -50,6 +65,7 @@ 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;
>      pwrite_field(fd, dpy->edid_info, dpy->edid_regs, link_state);
>      trace_vfio_display_edid_link_down();
> @@ -77,9 +93,8 @@ static void vfio_display_edid_update(VFIOPCIDevice *vdev, bool enabled,
>          goto err;
>      }
>  
> -    dpy->edid_regs->link_state = VFIO_DEVICE_GFX_LINK_STATE_UP;
> -    pwrite_field(fd, dpy->edid_info, dpy->edid_regs, link_state);
> -    trace_vfio_display_edid_link_up();
> +    timer_mod(dpy->edid_link_timer,
> +              qemu_clock_get_ms(QEMU_CLOCK_REALTIME) + 100);
>      return;
>  
>  err:
> @@ -140,6 +155,9 @@ 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;
>  
> @@ -158,6 +176,8 @@ 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,