[PATCH] drm/hyperv: Fix double mouse pointers

[PATCH] drm/hyperv: Fix double mouse pointers

[Dexuan Cui]

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@microsoft.com>
Cc: Deepak Rawat <drawat.floss@gmail.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
---
 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;
+	msg.ptr_pos.video_output = 0;
+	msg.ptr_pos.image_x = 0;
+	msg.ptr_pos.image_y = 0;
+	hyperv_sendpacket(hdev, &msg);
+
+	memset(&msg, 0, sizeof(struct synthvid_msg));
+	msg.vid_hdr.type = SYNTHVID_POINTER_SHAPE;
+	msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
+		sizeof(struct synthvid_pointer_shape);
+	msg.ptr_shape.part_idx = SYNTHVID_CURSOR_COMPLETE;
+	msg.ptr_shape.is_argb = 1;
+	msg.ptr_shape.width = 1;
+	msg.ptr_shape.height = 1;
+	msg.ptr_shape.hot_x = 0;
+	msg.ptr_shape.hot_y = 0;
+	msg.ptr_shape.data[0] = 0;
+	msg.ptr_shape.data[1] = 1;
+	msg.ptr_shape.data[2] = 1;
+	msg.ptr_shape.data[3] = 1;
+	hyperv_sendpacket(hdev, &msg);
+
+	return 0;
+}
+
 int hyperv_update_dirt(struct hv_device *hdev, struct drm_rect *rect)
 {
 	struct hyperv_drm_device *hv = hv_get_drvdata(hdev);
@@ -392,8 +426,11 @@ static void hyperv_receive_sub(struct hv_device *hdev)
 		return;
 	}
 
-	if (msg->vid_hdr.type == SYNTHVID_FEATURE_CHANGE)
+	if (msg->vid_hdr.type == SYNTHVID_FEATURE_CHANGE) {
 		hv->dirt_needed = msg->feature_chg.is_dirt_needed;
+		if (hv->dirt_needed)
+			hyperv_send_ptr(hv->hdev);
+	}
 }
 
 static void hyperv_receive(void *ctx)
-- 
2.25.1

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

[Haiyang Zhang]

> -----Original Message-----
> From: Dexuan Cui <decui@microsoft.com>
> Sent: Monday, September 13, 2021 2:27 PM
> To: drawat.floss@gmail.com; Haiyang Zhang <haiyangz@microsoft.com>;
> airlied@linux.ie; daniel@ffwll.ch; tzimmermann@suse.de; dri-
> devel@lists.freedesktop.org
> Cc: linux-hyperv@vger.kernel.org; linux-kernel@vger.kernel.org; Dexuan
> Cui <decui@microsoft.com>
> Subject: [PATCH] drm/hyperv: Fix double mouse pointers
> 
> 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@microsoft.com>
> Cc: Deepak Rawat <drawat.floss@gmail.com>
> Cc: Haiyang Zhang <haiyangz@microsoft.com>
> ---
>  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(-)

Thank you!
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>

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

[Deepak Rawat]

Thanks Dexuan, for the patch. A minor comment below.

On Mon, Sep 13, 2021 at 11:27 AM Dexuan Cui <decui@microsoft.com> 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@microsoft.com>
> Cc: Deepak Rawat <drawat.floss@gmail.com>
> Cc: Haiyang Zhang <haiyangz@microsoft.com>
> ---
>  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.

> +       msg.ptr_pos.video_output = 0;
> +       msg.ptr_pos.image_x = 0;
> +       msg.ptr_pos.image_y = 0;
> +       hyperv_sendpacket(hdev, &msg);
> +
> +       memset(&msg, 0, sizeof(struct synthvid_msg));
> +       msg.vid_hdr.type = SYNTHVID_POINTER_SHAPE;
> +       msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
> +               sizeof(struct synthvid_pointer_shape);
> +       msg.ptr_shape.part_idx = SYNTHVID_CURSOR_COMPLETE;
> +       msg.ptr_shape.is_argb = 1;
> +       msg.ptr_shape.width = 1;
> +       msg.ptr_shape.height = 1;
> +       msg.ptr_shape.hot_x = 0;
> +       msg.ptr_shape.hot_y = 0;
> +       msg.ptr_shape.data[0] = 0;
> +       msg.ptr_shape.data[1] = 1;
> +       msg.ptr_shape.data[2] = 1;
> +       msg.ptr_shape.data[3] = 1;
> +       hyperv_sendpacket(hdev, &msg);
> +

Is it necessary to send SYNTHVID_POINTER_SHAPE here? Perhaps we should
separate SYNTHVID_POINTER_POSITION and SYNTHVID_POINTER_SHAPE into
different functions.

> +       return 0;
> +}
> +
>  int hyperv_update_dirt(struct hv_device *hdev, struct drm_rect *rect)
>  {
>         struct hyperv_drm_device *hv = hv_get_drvdata(hdev);
> @@ -392,8 +426,11 @@ static void hyperv_receive_sub(struct hv_device *hdev)
>                 return;
>         }
>
> -       if (msg->vid_hdr.type == SYNTHVID_FEATURE_CHANGE)
> +       if (msg->vid_hdr.type == SYNTHVID_FEATURE_CHANGE) {
>                 hv->dirt_needed = msg->feature_chg.is_dirt_needed;
> +               if (hv->dirt_needed)
> +                       hyperv_send_ptr(hv->hdev);
> +       }
>  }
>
>  static void hyperv_receive(void *ctx)
> --
> 2.25.1
>

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

[Haiyang Zhang]

> -----Original Message-----
> From: Deepak Rawat <drawat.floss@gmail.com>
> Sent: Tuesday, September 14, 2021 11:59 AM
> To: Dexuan Cui <decui@microsoft.com>
> Cc: Haiyang Zhang <haiyangz@microsoft.com>; David Airlie
> <airlied@linux.ie>; Daniel Vetter <daniel@ffwll.ch>; Thomas Zimmermann
> <tzimmermann@suse.de>; dri-devel@lists.freedesktop.org; linux-
> hyperv@vger.kernel.org; linux-kernel@vger.kernel.org
> 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@microsoft.com> 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@microsoft.com>
> > Cc: Deepak Rawat <drawat.floss@gmail.com>
> > Cc: Haiyang Zhang <haiyangz@microsoft.com>
> > ---
> >  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

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

[Dexuan Cui]

> From: Deepak Rawat <drawat.floss@gmail.com>
> Sent: Tuesday, September 14, 2021 8:59 AM
> ...
> > +/* 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.

According to my test, "is_visible = 0" doesn't work, i.e. can't hide the
unwanted HW mouse poiner. It looks like the field is for some very old
legacy Windows VMs like Windows Vista.

Haiyang also replied in another email, saying "is_visible = 0" doesn't
work.

> > +       msg.ptr_pos.video_output = 0;
> > +       msg.ptr_pos.image_x = 0;
> > +       msg.ptr_pos.image_y = 0;
> > +       hyperv_sendpacket(hdev, &msg);
> > +
> > +       memset(&msg, 0, sizeof(struct synthvid_msg));
> > +       msg.vid_hdr.type = SYNTHVID_POINTER_SHAPE;
> > +       msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
> > +               sizeof(struct synthvid_pointer_shape);
> > +       msg.ptr_shape.part_idx = SYNTHVID_CURSOR_COMPLETE;
> > +       msg.ptr_shape.is_argb = 1;
> > +       msg.ptr_shape.width = 1;
> > +       msg.ptr_shape.height = 1;
> > +       msg.ptr_shape.hot_x = 0;
> > +       msg.ptr_shape.hot_y = 0;
> > +       msg.ptr_shape.data[0] = 0;
> > +       msg.ptr_shape.data[1] = 1;
> > +       msg.ptr_shape.data[2] = 1;
> > +       msg.ptr_shape.data[3] = 1;
> > +       hyperv_sendpacket(hdev, &msg);
> > +
> 
> Is it necessary to send SYNTHVID_POINTER_SHAPE here? Perhaps we should

According to my test, yes. If I don't send a SYNTHVID_POINTER_SHAPE message,
the unwanted mouse pointer can't be hidden. As we know, the protocol between
the VSC and the VSP is not well documented to us. I can ask Hyper-V
team for some clarification on this, but it's probably we can just use the current
version of hiding the mouse pointer as-is -- this has been used for 10+ years
in the hyperv_fb driver without any issue. :-)

> separate SYNTHVID_POINTER_POSITION and SYNTHVID_POINTER_SHAPE into
> different functions.

Since the 2 messages are only used here, I suggest we keep it as-is.

Thanks,
-- Dexuan

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

[Deepak Rawat]

HI Dexuan, thanks for confirming. Could you please add this as a
comment to the function.

Reviewed-by: Deepak Rawat <drawat.floss@gmail.com>

On Tue, Sep 14, 2021 at 11:59 PM Dexuan Cui <decui@microsoft.com> wrote:
>
> > From: Deepak Rawat <drawat.floss@gmail.com>
> > Sent: Tuesday, September 14, 2021 8:59 AM
> > ...
> > > +/* 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.
>
> According to my test, "is_visible = 0" doesn't work, i.e. can't hide the
> unwanted HW mouse poiner. It looks like the field is for some very old
> legacy Windows VMs like Windows Vista.
>
> Haiyang also replied in another email, saying "is_visible = 0" doesn't
> work.
>
> > > +       msg.ptr_pos.video_output = 0;
> > > +       msg.ptr_pos.image_x = 0;
> > > +       msg.ptr_pos.image_y = 0;
> > > +       hyperv_sendpacket(hdev, &msg);
> > > +
> > > +       memset(&msg, 0, sizeof(struct synthvid_msg));
> > > +       msg.vid_hdr.type = SYNTHVID_POINTER_SHAPE;
> > > +       msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
> > > +               sizeof(struct synthvid_pointer_shape);
> > > +       msg.ptr_shape.part_idx = SYNTHVID_CURSOR_COMPLETE;
> > > +       msg.ptr_shape.is_argb = 1;
> > > +       msg.ptr_shape.width = 1;
> > > +       msg.ptr_shape.height = 1;
> > > +       msg.ptr_shape.hot_x = 0;
> > > +       msg.ptr_shape.hot_y = 0;
> > > +       msg.ptr_shape.data[0] = 0;
> > > +       msg.ptr_shape.data[1] = 1;
> > > +       msg.ptr_shape.data[2] = 1;
> > > +       msg.ptr_shape.data[3] = 1;
> > > +       hyperv_sendpacket(hdev, &msg);
> > > +
> >
> > Is it necessary to send SYNTHVID_POINTER_SHAPE here? Perhaps we should
>
> According to my test, yes. If I don't send a SYNTHVID_POINTER_SHAPE message,
> the unwanted mouse pointer can't be hidden. As we know, the protocol between
> the VSC and the VSP is not well documented to us. I can ask Hyper-V
> team for some clarification on this, but it's probably we can just use the current
> version of hiding the mouse pointer as-is -- this has been used for 10+ years
> in the hyperv_fb driver without any issue. :-)
>
> > separate SYNTHVID_POINTER_POSITION and SYNTHVID_POINTER_SHAPE into
> > different functions.
>
> Since the 2 messages are only used here, I suggest we keep it as-is.
>
> Thanks,
> -- Dexuan

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

[Dexuan Cui]

> From: Deepak Rawat <drawat.floss@gmail.com>
> Sent: Thursday, September 16, 2021 9:17 AM
> To: Dexuan Cui <decui@microsoft.com>
> Cc: Haiyang Zhang <haiyangz@microsoft.com>; David Airlie <airlied@linux.ie>;
> Daniel Vetter <daniel@ffwll.ch>; Thomas Zimmermann
> <tzimmermann@suse.de>; dri-devel@lists.freedesktop.org;
> linux-hyperv@vger.kernel.org; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH] drm/hyperv: Fix double mouse pointers
> 
> HI Dexuan, thanks for confirming. Could you please add this as a
> comment to the function.
> 
> Reviewed-by: Deepak Rawat <drawat.floss@gmail.com>

Thanks, Deepak! 
Will do, and I'll rename the function to hyperv_hide_hw_ptr() to
better express the intent of the function.