[vbox-dev] Have any non-Linux developers looked at the vboxvideo drm/kms driver?

Michael Thayer michael.thayer at oracle.com
Wed Feb 8 13:35:51 GMT 2017

Hello Jan,

08.02.2017 14:14, Jan Petrouš wrote:
> On 8 February 2017 at 13:45, Michael Thayer <michael.thayer at oracle.com
> <mailto:michael.thayer at oracle.com>> wrote:
>> I'm afraid I will have to ask for a bit of clarification there.  My
> understanding of a frame buffer is an area of (usually video) memory
> representing the image shown on a screen.  You can have more or less as
> many of those as will fit into video memory and flip between them.  You
> can also have up to 32 virtual screens (the hardware supports 64).
> Ok, I might describe it vague, so yes - I need more virtual screens each
> of them with support of framebuffer. So if I enable, for ex. 4 screens
> (or monitors?), then I expect to have also /dev/fb0 - /dev/fb3 devices,
> writing to which will be displayed on appropriate virtual screen.
That is less vague now - you mean Linux frame buffer devices.  Currently 
no plans for that, but our driver code is probably not the right place 
to do it anyway: we use the generic fbdev-on-KMS wrapper in the Linux 
kernel, so unless we are using it wrongly in some way (and I just 
checked that my two-screen host also only provides one fbdev device) you 
would need to talk to the kernel drm maintainers about it[1].


[1] https://lists.freedesktop.org/archives/dri-devel/
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