Re: Cygwin X11 on second (Nvidia) graphics card

[Franz Fehringer <fehrin2@gmail.com>]

Am 27.01.2023 um 16:22 schrieb Franz Fehringer via Cygwin:
> Hi,
> 
> I have a question which seems quite natural but i cannot find anything 
> useful using google & co.
> My (business) notebook has two graphics cards, one builtin identifying 
> as Intel Iris Xe and an additional one, a Nvidia MX550.
> I start X11 (xwin) with defaults (-listen tcp is the only extra option).
> Using nvidia-smi and the Nvidia activity dialog i see that the Nvidia 
> graphics card is not used.
> Using glxinfo i see that the builtin Intel Iris Xe is used instead.
> I already prefer Nvidia over Intel via the Nvidia control panel.
> How do i make X11 and OpenGL use the Nvidia graphics card instead of the 
> Intel one?
> 
> Thx in advance
> 
> Franz
> 
> 
> 
Investigating the issue further (incorporating the answers i got) the 
situation looks as follows:
Both the builtin display and the external HDMI connected monitor are 
connected to the internal Intel graphics card at first glance.
The idea in this constellation is that the user can decide both as a 
general preference and application wise if the second graphics card 
(better performance and higher power consumption) ot the first (builtin) 
one is used.
These settings are duplicated (Nvidia control *and* M$ system control), 
i use identical settings utilizing both approaches.
Now the XWin executable does not use the Nvidia graphics card.
But Cygwin executables like glxinfo or glxspheres do if i assign them 
specifically to the Nvidia graphics card using the settings mentioned 
(only setting the general preference does not suffice while it is 
sufficient for several non Cygwin programs like teams or msedge).
In a sense the XWin server using the Nvidia graphics card would amount 
to a (sort of) headless mode (graphics card but no monitor), at least 
this is what i think: The XWin server does not use the Nvidia graphics 
card because it is not connected to a display (monitor).
This is otherwise a valid scenario in the VirtualGL realm for example 
and there is a short explanation how make this (i.e. X11 uses graphics 
card with no monitor connected) work:
https://virtualgl.org/Documentation/HeadlessNV
In summary it seems to me that in this specific situation there is no 
easy way to make XWin use the Nvidia graphics card, but i may well be 
corrected about this.
It would be interesting what someone like Jon Turney has to say about this.
And i am still surprised that this seems to have been not discussed so far.
Thanks to all who answered (and those who will be answering).