Retrieving monitor connection information
I have an application that requires the equivalent of the `ConnectorNumber` and `ConnectorType` properties that are available in the RandR protocol in X11 (see https://github.com/freedesktop/xorg-xorgproto/blob/master/randrproto.txt) For various reasons related to multi-monitor setups and refresh rates I'd prefer to run this application under Wayland (It's implemented in GTK4 and I'm seeing significant performance degradation under X versus Wayland) Is there a way of retrieving these properties under Wayland? I know they are provided by the NVidia driver. I'm open to providing some sort of patch to do this myself but unsure where to look. Thanks, Andrew. -- Andrew Marshall Independent C++ Consultant https://www.algodynamic.co.uk/ https://github.com/planetmarshall https://www.linkedin.com/in/algodynamic/
Re: Retrieving monitor connection information
Hi, On Thursday, September 1st, 2022 at 11:23, Andrew Marshall wrote: > I have an application that requires the equivalent of the > `ConnectorNumber` and `ConnectorType` properties that are available > in the RandR protocol in X11 (see > https://github.com/freedesktop/xorg-xorgproto/blob/master/randrproto.txt) There is no equivalent to X11's RandR extension in Wayland. Why do you need to fetch this information? What's your use-case? Thanks, Simon
Re: Retrieving monitor connection information
On Thu, 1 Sept 2022 at 10:27, Simon Ser wrote: > Hi, > > On Thursday, September 1st, 2022 at 11:23, Andrew Marshall < > and...@algodynamic.com> wrote: > > > I have an application that requires the equivalent of the > > `ConnectorNumber` and `ConnectorType` properties that are available > > in the RandR protocol in X11 (see > > https://github.com/freedesktop/xorg-xorgproto/blob/master/randrproto.txt > ) > > There is no equivalent to X11's RandR extension in Wayland. > No, but the information is available - so there must be a means of retrieving that information? > > Why do you need to fetch this information? What's your use-case? > > A medical device outputs a camera display to each of four monitors, attached to display port connectors on the graphics card. There is a 1:1 relationship between camera outputs and displays, and a UI allows assigning a specific camera output to a specific display port output. -- Andrew Marshall Independent C++ Consultant https://www.algodynamic.co.uk/ https://github.com/planetmarshall https://www.linkedin.com/in/algodynamic/
Re: Retrieving monitor connection information
On Thursday, September 1st, 2022 at 12:23, Andrew Marshall wrote: > > Why do you need to fetch this information? What's your use-case? > > A medical device outputs a camera display to each of four monitors, > attached to display port connectors on the graphics card. There is a > 1:1 relationship between camera outputs and displays, and a UI allows > assigning a specific camera output to a specific display port output. It seems like wl_output.name would be useful for this purpose. wl_output.description contains a human-readable string which can be included in the UI. Note, do not assume that wl_output.name will have any defined format. Some compositors will send e.g. "DP-2", some will send an arbitrary ID such as "CD6767WZ", etc.
Re: Retrieving monitor connection information
On Thu Sep 1, 2022 at 6:23 AM EDT, Andrew Marshall wrote: > No, but the information is available - so there must be a means of > retrieving that information? Not without a protocol. > A medical device outputs a camera display to each of four monitors, > attached to display port connectors on the graphics card. There is a 1:1 > relationship between camera outputs and displays, and a UI allows assigning > a specific camera output to a specific display port output. Maybe you can find your way around using the drm-lease-v1 [1] protocol, but it would be a bit hacky and a lot of work. [1]: https://gitlab.freedesktop.org/wayland/wayland-protocols/-/blob/main/staging/drm-lease/drm-lease-v1.xml
Re: Retrieving monitor connection information
On 1 Sep 2022, at 12:26, Simon Ser wrote: >> A medical device outputs a camera display to each of four monitors, >> attached to display port connectors on the graphics card. There is a >> 1:1 relationship between camera outputs and displays, and a UI allows >> assigning a specific camera output to a specific display port output. > > It seems like wl_output.name would be useful for this purpose. > wl_output.description contains a human-readable string which can be > included in the UI. > > Note, do not assume that wl_output.name will have any defined format. > Some compositors will send e.g. "DP-2", some will send an arbitrary ID > such as "CD6767WZ", etc. In the described use-case compositor is most likely known and fixed. Best, Mikhail.
Re: Retrieving monitor connection information
On Thu, 1 Sept 2022 at 12:01, Mikhail Gusarov wrote: > > In the described use-case compositor is most likely known and fixed. > > Yes, however can I guarantee that the output names will remain the same in the following scenarios - * Rebooting of the system * Disconnection and reconnection of display devices ? Thanks, Andrew. -- Andrew Marshall Independent C++ Consultant https://www.algodynamic.co.uk/ https://github.com/planetmarshall https://www.linkedin.com/in/algodynamic/
Re: Retrieving monitor connection information
For example, the advantage of having connection information is that I can provide the following behaviour: 1. User assigns Camera 1 to DisplayPort1 2. User disconnects DisplayPort1 3. User connects a new monitor to DisplayPort1 4. Camera 1 is restored on the new monitor. Regards, Andrew. On Thu, 1 Sept 2022 at 12:36, Andrew Marshall wrote: > > On Thu, 1 Sept 2022 at 12:01, Mikhail Gusarov > wrote: > >> >> In the described use-case compositor is most likely known and fixed. >> >> > Yes, however can I guarantee that the output names will remain the same in > the following scenarios - > > * Rebooting of the system > * Disconnection and reconnection of display devices > > ? > > Thanks, > Andrew. > -- > Andrew Marshall > Independent C++ Consultant > https://www.algodynamic.co.uk/ > https://github.com/planetmarshall > https://www.linkedin.com/in/algodynamic/ > -- Andrew Marshall Independent C++ Consultant https://www.algodynamic.co.uk/ https://github.com/planetmarshall https://www.linkedin.com/in/algodynamic/
Re: Retrieving monitor connection information
On Thursday, September 1st, 2022 at 13:36, Andrew Marshall
wrote:
> On Thu, 1 Sept 2022 at 12:01, Mikhail Gusarov wrote:
>
> >
> > In the described use-case compositor is most likely known and fixed.
>
> Yes, however can I guarantee that the output names will remain the same in
> the following scenarios -
>
> * Rebooting of the system
> * Disconnection and reconnection of display devices
>
> ?
No. KMS names ("DP-2") cannot be used for a reliable identifier.
wl_output.name specification states:
The name is not guaranteed to be persistent across sessions, thus cannot
be used to reliably identify an output in e.g. configuration files.
See the discussion at [1] for more info. To fix this, we'd need a new
wl_output event and a new KMS property.
[1]:
https://gitlab.freedesktop.org/wayland/wayland/-/merge_requests/109#note_813539
