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

-----Original Message-----
From: Deepak Rawat <redacted>
Sent: Tuesday, September 14, 2021 11:59 AM
To: Dexuan Cui <decui@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>; David Airlie
[off-list ref]; Daniel Vetter [off-list ref]; Thomas Zimmermann
[off-list ref]; 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 [off-list ref] wrote:

quoted

It looks like Hyper-V supports a hardware cursor feature. It is not

used

quoted

by Linux VM, but the Hyper-V host still draws a point as an extra

mouse

quoted

pointer, which is unwanted, especially when Xorg is running.

The hyperv_fb driver uses synthvid_send_ptr() to hide the unwanted

pointer.

quoted

When the hyperv_drm driver was developed, the function

synthvid_send_ptr()

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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")

quoted

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: Deepak Rawat <redacted>
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

++++++++++++++++++++-

quoted

 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

quoted

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);

quoted

 int hyperv_update_vram_location(struct hv_device *hdev, phys_addr_t

vram_pp);

quoted

 int hyperv_update_situation(struct hv_device *hdev, u8 active, u32

bpp,

quoted

                            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

quoted

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,

quoted

        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);

quoted

+       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

quoted

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,

quoted

        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