[Mesa-dev] Manipulate GALLIUM_HUD post-launch (interactively)

[Eero Tamminen]

Hi,

On 10/28/2015 11:24 PM, Jimmy Berry wrote:
> I have found myself desiring the ability to manipulate the GALLIUM_HUD
> variable while an application is running. At the most basic simply
> being able to toggle the hud on and off would be great. Otherwise, one
> has to relaunch an application and get back to the same state which
> may not always be trivial.
>
> Obviously there are a lot of other possibilities for such a mechanism
> even manipulating other variables interactively.
>
> I discussed the idea with imirkin_ on #dri-devel who agreed that
> something like a socket interface would be a reasonable way to
> approach the problem, but suggested I toss out the idea on the mailing
> list to acquire more thoughts.
>
> I have extensive development experience, but none in the kernel nor
> mesa space. If desirable I would be interested in attempting to
> implement this idea.

Some other possibilities than socket:

* Using (non-blocking) fifo, so that it can be more easily controlled 
from shell script than with socket

* Using signal to toggle the HUD

Signal handler should be set only when user requests it, e.g. with 
environment variable (that way Mesa doesn't by itself steal signals from 
applications).


	- Eero