I'm adding features to VKMS! What would you like to see?

[Simon Ser]

Hi!

On Thursday, July 28th, 2022 at 20:54, Jim Shargo <jshargo at chromium.org> wrote:

> TL;DR: I'm working on extending VKMS and wanted feedback from other
> compositor/wayland devs.

Very nice, thanks for reaching out!

> - What VKMS features could help your testing the most?

I think the most valuable features are the ones which typically require
special hw to test (such as DP-MST hub, HDR monitor, bad DP cable…).

Here are a few ideas:

- Connector hotplug (switch status from disconnected to connected and
  back)
- Connector registering as it happens on DP-MST setups (new connectors
  appearing, old connectors disappearing)
- Basic format modifier support (to make sure that code-path is tested
  in CI)
- link-status change emulation
- FB_DAMAGE_CLIPS handling
- Multiple planes with customizable constraints (not sure how this
  would look like yet)
- A handful of simpler props like panel_orientation, non-desktop, TILE,
  etc

> - How much do you care about writeback buffer support vs CRC checks
> in tests atm?

Maybe a question for Pekka?

> - What kinds of bugs do you get around DRM/KMS?

I think most bugs are around modesets (black screens). This may sound
pretty basic, but it sounds like hw differences (ie. large test matrix
and different limitations), hubs and different sequences of user actions
(plug/unplug/config changes) make turning on a display a complicated
operation. Or maybe it's the most noticeable bug, so users are more
likely to open a bug report for it. (Note, sometimes the bug ends up
being a driver issue.)

Hope this helps,

Simon