[vlc-devel] [PATCH 2/2] linux: Add for kms vout plugin possibility to choose output display

Juha-Pekka Heikkila juhapekka.heikkila at gmail.com
Tue Jan 15 13:24:10 CET 2019

On 14.1.2019 21.43, Rémi Denis-Courmont wrote:
> Le maanantaina 14. tammikuuta 2019, 21.09.35 EET Juha-Pekka Heikkilä a écrit :
>> I tried change_integer_cb() but my callback to populate the list was
>> never called.
> With that logic, we'd put the whole CLI help in debug messages just because it
> is "never shown". Come on.

What do you mean "never shown"? I wrote the callback gets never called, 
there's no special logic involved in this. Those linked email also 
talked there is wish *not* to get it fixed for CLI to which I have no 
opinion about.

If I now go with stable VLC do "vlc -H" and look for xcb_xv which I know 
uses "change_integer_cb()" for xvideo-adaptor what I get is this:

  XVideo output (XCB) (xcb_xv)
       --xvideo-adaptor <integer [-2147483648 .. 2147483647]>
                                  XVideo adaptor number
           XVideo hardware adaptor to use. By default, VLC will use the 
           functional adaptor.
       --xvideo-format-id <integer [-2147483648 .. 2147483647]>
                                  XVideo format id
           XVideo image format id to use. By default, VLC will try to 
use the
           best match for the video being played.

Those 2147483647 numbers don't look right. :( I got same behavior with 
my attempt on my module and if I try to use those callback parameters 
from CLI without giving any number there it freezes VLC on me.

This is where I have that chicken-egg problem. Those callbacks do work 
from GUI as expected but when I'm running with features where GUI really 
cannot be used because it kills execution of KMS module it's bit of a 
bummer. KMS module has the need to become drmmaster and there can be 
only one at a time. If something else (gui for example) has set up 
graphics on screen that something else is drmmaster when I'm doing query 
for that right.


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