Hi Thomas,
On Thu, 23 Jan 2020 at 09:21, Thomas Zimmermann tzimmermann@suse.de wrote:
@@ -174,12 +174,22 @@ struct drm_crtc_state { * @no_vblank: * * Reflects the ability of a CRTC to send VBLANK events. This state
* usually depends on the pipeline configuration, and the main usuage* is CRTCs feeding a writeback connector operating in oneshot mode.* In this case the VBLANK event is only generated when a job is queued* to the writeback connector, and we want the core to fake VBLANK* events when this part of the pipeline hasn't changed but others had* or when the CRTC and connectors are being disabled.
* usually depends on the pipeline configuration. If set to true, DRM* atomic helpers will sendout a fake VBLANK event during display* updates.** One usage is for drivers and/or hardware without support for VBLANK* interrupts. Such drivers typically do not initialize vblanking* (i.e., call drm_vblank_init() wit the number of CRTCs). For CRTCs* without initialized vblanking, the field is initialized to true and* a VBLANK event will be send out on each update of the display* pipeline.** Another usage is CRTCs feeding a writeback connector operating in* oneshot mode. In this case the VBLANK event is only generated when* a job is queued to the writeback connector, and we want the core* to fake VBLANK events when this part of the pipeline hasn't changed* but others had or when the CRTC and connectors are being disabled. *
Perhaps it's just me, yet the following ideas would make the topic significantly easier and clearer.
- adding explicit "fake" when talking about drm/atomic _helpers_ generating/sending a VBLANK event. For example, in 15/15 the commit message says "fake", while inline comment omits it... Leading to the confusion pointed out.
- s/no_vblank/fake_vblank/g or s/no_vblank/no_hw_vblank/g Simple and concise. With slight inclination towards the former wording :-)
If you and Daniel agree with the rename, then the first sentence of the description should probably be tweaked.
HTH Emil