From: linux-hyperv-owner@vger.kernel.org
[off-list ref] On Behalf Of Dexuan Cui
Sent: Thursday, September 12, 2019 11:39 PM
To: Michael Kelley <redacted>; Wei Hu <redacted>;
b.zolnierkie@samsung.com; linux-hyperv@vger.kernel.org;
dri-devel@lists.freedesktop.org; linux-fbdev@vger.kernel.org;
linux-kernel@vger.kernel.org; Stephen Hemminger
[off-list ref]; sashal@kernel.org; Haiyang Zhang
[off-list ref]; KY Srinivasan [off-list ref]
Cc: Iouri Tarassov <redacted>
Subject: RE: [PATCH v4] video: hyperv: hyperv_fb: Obtain screen resolution
from Hyper-V host

quoted

From: Michael Kelley <redacted>
Sent: Thursday, September 5, 2019 7:06 AM

From: Wei Hu <redacted> Sent: Thursday, September 5, 2019

2:12

quoted

AM

quoted

Beginning from Windows 10 RS5+, VM screen resolution is obtained from

host.

quoted

The "video=hyperv_fb" boot time option is not needed, but still can be
used to overwrite what the host specifies. The VM resolution on the host
could be set by executing the powershell "set-vmvideo" command.

Signed-off-by: Iouri Tarassov <redacted>
Signed-off-by: Wei Hu <redacted>
---
    v2:
    - Implemented fallback when version negotiation failed.
    - Defined full size for supported_resolution array.

    v3:
    - Corrected the synthvid major and minor version comparison

problem.

quoted

quoted

    v4:
    - Changed function name to synthvid_ver_ge().

 drivers/video/fbdev/hyperv_fb.c | 159

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

quoted

 1 file changed, 147 insertions(+), 12 deletions(-)

Reviewed-by: Michael Kelley <redacted>

Looks good to me.

Reviewed-by: Dexuan Cui <decui@microsoft.com>

Hi Wei,
It turns out we need to make a further fix. :-)

The patch forgets to take par->update into consideration.

When the VM Connection window is closed (or minimized?),
the host sends a message to the guest, and the guest sets
par->update to false in synthvid_recv_sub().

If par->update is false, the guest doesn't need to call
synthvid_update().

Thanks,
-- Dexuan