[PATCH] xRandr strikes back

[Dave Airlie]

On Mon, Mar 11, 2013 at 2:09 AM, Hardening <rdp.effort at gmail.com> wrote:
> On 10/03/2013 16:17, Jonas Ådahl wrote:
>> On Sun, Mar 10, 2013 at 3:53 PM, Hardening <rdp.effort at gmail.com> wrote:
>>> This patch adds a wlrandr extension. It is useful to test
>>> mode switching. The patch provides the weston-switch-mode
>>> utility that can be use quite the same way as xrandr to
>>> change graphical modes. For now only the DRM backend supports
>>> mode switching, but other may follow.
>>
>> Hi,
>>
>> I think the consensus has been not to have a protocol like this as
>> clients should not dictate what resolution an output should have. A
>> client can ask nicely via the fullscreen API a preferred resolution,
>> but it should not set it. The point with this is that no client should
>> be able to change resolution, crash, and then leave the compositor in
>> an invalid state (read wrong resolution). The shell, however, can have
>> its own private protocol for doing this, and then whatever user
>> interface wants to have to change resolution, but it should not be in
>> a client facing protocol.
>>
> hi,
> the current API only allows to switch to mode listed by backends, can we
> assume that this list is sane ?
>
> For the issue with a client dying and leaving the compositor in a weird
> resolution. Perhaps the API could change so that clients can specify
> that the resolution change is contextual, and the previous resolution
> would be set back when the client dies (it would look like the exclusive
> part of the screenshooter).
>

People shouldn't confuse the requirements for something like a control
panel displays applet or command line mode switcher, for the case that a
user wants to switch resolution, from the case where an app wants to switch.

User directed modesetting doesn't require app tracking, app directed
modesetting is best handled by the fullscreen + size hinting protocol.

As long as the app directed is in place and apps knows to use it, then
having a user directed one is required in some way for control panel type
things.

Dave.