| Summary: | Vsync disabled: slowmotion effects or wrong fps? | ||
|---|---|---|---|
| Product: | [Plasma] kwin | Reporter: | Antonio Orefice <kokoko3k> |
| Component: | effects-various | Assignee: | KWin default assignee <kwin-bugs-null> |
| Status: | RESOLVED NOT A BUG | ||
| Severity: | normal | ||
| Priority: | NOR | ||
| Version First Reported In: | 5.8.3 | ||
| Target Milestone: | --- | ||
| Platform: | Other | ||
| OS: | Linux | ||
| Latest Commit: | Version Fixed In: | ||
| Sentry Crash Report: | |||
| Attachments: | supportinformation from kwin when running without vsync enabled | ||
|
Description
Antonio Orefice
2016-11-21 15:17:40 UTC
Ok, i've to add several information to this report, sorry. The slowness was due to a setting i have in my kwinrc: MaxFPS=300 I have to specify it because: 1) with vsync disabled, kwin render frames at 60hz, why? i don't know. 2) i switch between 60hz and 75hz and 300 is the closer multiple integer to both. Custom misconfiguration too high max frame per second. If you need support please use a support channel like forum.kde.org, but bugs.kde.org is not a support forum. Hi Martin, thanks for answering. The real issue here, is that kwin is unable to detect the right refresh rate when vsync is disabled. Can we continue here or should i open another bug report about that? Or maybe even that would be marked as invalid? KWin is able to detect the refresh rate. If you configure your driver in a way that it breaks KWin that is hardly a problem we care about. Just don't do it then. Hi again, maybe there is a misunderstanding here, sorry. The problem i have with limited framerate does not depend on the driver settings, I'm able to reproduce it even without nvidia's ForceFullCompositionPipeline=On What happens, is that if i remove MaxFPS= line from kwinrc and disable any "tearing prevention" in the compositor settings, kwin seems to render things at 60..62fps. I gather this information: 1- From the kwin's "Show FPS" effect: it shows 60..62 fps 2- by observing the windows edges while i drag it: If kwin's render rate were close to the display refresh, i'd expect to see smooth window dragging with a single "tearing" line, and this is indeed what happens if i specify MaxFPS=75 OR if i switch to a 60hz mode. But what happens is that the movement is jerky and there are several tearing lines/artifacts. As soon as i enable kwin's Tearing prevention ON (the method doesn't matter), the fps effect jumps to 75, i repeat, this happens with AND without any special driver configuration. Thanks for your attention. > I gather this information:
> 1- From the kwin's "Show FPS" effect:
> it shows 60..62 fps
The effect clearly states that it's not a benchmark. The number doesn't say
anything.
The way to check what kwin picks is in the supportInformation.
Created attachment 102386 [details]
supportinformation from kwin when running without vsync enabled
and it picks: Refresh Rate: 75.0247 for both monitors with and without tearing prevention enabled, which should be fine... What puzzles me is why window movements are: *jerky: with vsync disabled and screen at 75hz *smooth: with vsync enabled at any refresh rate with vsync disabled and screen at 60hz with vsync disabled and screen at 75hz but MaxFPS=75 specified in kwinrc |