RE: [PATCH] drm/hyperv: Fix double mouse pointers

[Haiyang Zhang]

> -----Original Message-----
> From: Deepak Rawat <drawat.floss@xxxxxxxxx>
> Sent: Tuesday, September 14, 2021 11:59 AM
> To: Dexuan Cui <decui@xxxxxxxxxxxxx>
> Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>; David Airlie
> <airlied@xxxxxxxx>; Daniel Vetter <daniel@xxxxxxxx>; Thomas Zimmermann
> <tzimmermann@xxxxxxx>; dri-devel@xxxxxxxxxxxxxxxxxxxxx; linux-
> hyperv@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH] drm/hyperv: Fix double mouse pointers
> 
> Thanks Dexuan, for the patch. A minor comment below.
> 
> On Mon, Sep 13, 2021 at 11:27 AM Dexuan Cui <decui@xxxxxxxxxxxxx> wrote:
> >
> > It looks like Hyper-V supports a hardware cursor feature. It is not
> used
> > by Linux VM, but the Hyper-V host still draws a point as an extra
> mouse
> > pointer, which is unwanted, especially when Xorg is running.
> >
> > The hyperv_fb driver uses synthvid_send_ptr() to hide the unwanted
> pointer.
> > When the hyperv_drm driver was developed, the function
> synthvid_send_ptr()
> > was not copied from the hyperv_fb driver. Fix the issue by adding the
> > function into hyperv_drm.
> >
> > Fixes: 76c56a5affeb ("drm/hyperv: Add DRM driver for hyperv synthetic
> video device")
> > Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
> > Cc: Deepak Rawat <drawat.floss@xxxxxxxxx>
> > Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
> > ---
> >  drivers/gpu/drm/hyperv/hyperv_drm.h         |  1 +
> >  drivers/gpu/drm/hyperv/hyperv_drm_modeset.c |  1 +
> >  drivers/gpu/drm/hyperv/hyperv_drm_proto.c   | 39
> ++++++++++++++++++++-
> >  3 files changed, 40 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/hyperv/hyperv_drm.h
> b/drivers/gpu/drm/hyperv/hyperv_drm.h
> > index 886add4f9cd0..27bfd27c05be 100644
> > --- a/drivers/gpu/drm/hyperv/hyperv_drm.h
> > +++ b/drivers/gpu/drm/hyperv/hyperv_drm.h
> > @@ -46,6 +46,7 @@ int hyperv_mode_config_init(struct hyperv_drm_device
> *hv);
> >  int hyperv_update_vram_location(struct hv_device *hdev, phys_addr_t
> vram_pp);
> >  int hyperv_update_situation(struct hv_device *hdev, u8 active, u32
> bpp,
> >                             u32 w, u32 h, u32 pitch);
> > +int hyperv_send_ptr(struct hv_device *hdev);
> >  int hyperv_update_dirt(struct hv_device *hdev, struct drm_rect *rect);
> >  int hyperv_connect_vsp(struct hv_device *hdev);
> >
> > diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_modeset.c
> b/drivers/gpu/drm/hyperv/hyperv_drm_modeset.c
> > index 3aaee4730ec6..e21c82cf3326 100644
> > --- a/drivers/gpu/drm/hyperv/hyperv_drm_modeset.c
> > +++ b/drivers/gpu/drm/hyperv/hyperv_drm_modeset.c
> > @@ -101,6 +101,7 @@ static void hyperv_pipe_enable(struct
> drm_simple_display_pipe *pipe,
> >         struct hyperv_drm_device *hv = to_hv(pipe->crtc.dev);
> >         struct drm_shadow_plane_state *shadow_plane_state =
> to_drm_shadow_plane_state(plane_state);
> >
> > +       hyperv_send_ptr(hv->hdev);
> >         hyperv_update_situation(hv->hdev, 1,  hv->screen_depth,
> >                                 crtc_state->mode.hdisplay,
> >                                 crtc_state->mode.vdisplay,
> > diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_proto.c
> b/drivers/gpu/drm/hyperv/hyperv_drm_proto.c
> > index 6d4bdccfbd1a..1ea7a0432320 100644
> > --- a/drivers/gpu/drm/hyperv/hyperv_drm_proto.c
> > +++ b/drivers/gpu/drm/hyperv/hyperv_drm_proto.c
> > @@ -299,6 +299,40 @@ int hyperv_update_situation(struct hv_device
> *hdev, u8 active, u32 bpp,
> >         return 0;
> >  }
> >
> > +/* Send mouse pointer info to host */
> > +int hyperv_send_ptr(struct hv_device *hdev)
> > +{
> > +       struct synthvid_msg msg;
> > +
> > +       memset(&msg, 0, sizeof(struct synthvid_msg));
> > +       msg.vid_hdr.type = SYNTHVID_POINTER_POSITION;
> > +       msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
> > +               sizeof(struct synthvid_pointer_position);
> > +       msg.ptr_pos.is_visible = 1;
> 
> "is_visible" should be 0 since you want to hide the pointer. Maybe
> better, accept these from the caller.

I believe I tried is_visible = 0 during my implementation of the hyperv_fb. It still have the host cursor visible... So I had to set the cursor color's alpha value = 0 to make it transparent. But you may try is_visible = 0 again.

Thanks,
- Haiyang