Re: [PATCH v9 5/7] vfio: Define vfio based dma-buf operations

From: Kirti Wankhede
Date: Wed Jul 12 2017 - 09:19:02 EST

Hey Gerd,

Sorry, I missed this mail earlier.

On 6/21/2017 12:52 PM, Gerd Hoffmann wrote:
> Hi,
>> We don't support cursor for console vnc. Ideally console vnc should
>> be
>> used by admin for configuration or during maintenance, which refresh
>> primary surface at low refresh rate, 10 fps.
> But you surely want a mouse pointer for the admin?
> You render it directly to the primary surface then I guess?

If cursor surface is not provided, a dot for cursor is seen on the
primary surface, which is pretty much usable.

>> Right we need to know this at device initialization time for both
>> cases
>> to initialize VGACommonState structure for that device
> Why do you need a VGACommonState?

We need to create a GRAPHIC_CONSOLE for vGPU device and specify
GraphicHwOps so that from its .gfx_update callback, surface can be
queried and updated.

>> and also need
>> NONE to decide whether to init console vnc or not. We have a
>> mechanism
>> to disable console vnc path and we recommend to disable it for better
>> performance.
> Hmm, maybe we should have a ioctl to configure the refresh rate, or a
> ioctl to allow qemu ask for a refresh when needed?

What is default refresh rate of QEMU if vnc is connected?


> qemu can throttle the display update rate, which for example happens in
> case no vnc client is connected. qemu updates the display only once
> every few seconds then.
> cheers,
> Gerd