[PATCH v15 3/5] drm: renesas: Add RZ/G2L DU Support

[Maxime Ripard]

On Fri, Dec 15, 2023 at 01:52:28PM +0000, Biju Das wrote:
> > > > > > > +static int rzg2l_du_crtc_enable_vblank(struct drm_crtc *crtc) {
> > > > > > > +	struct rzg2l_du_crtc *rcrtc = to_rzg2l_crtc(crtc);
> > > > > > > +
> > > > > > > +	rcrtc->vblank_enable = true;
> > > > > > > +
> > > > > > > +	return 0;
> > > > > > > +}
> > > > > > > +
> > > > > > > +static void rzg2l_du_crtc_disable_vblank(struct drm_crtc *crtc)
> > {
> > > > > > > +	struct rzg2l_du_crtc *rcrtc = to_rzg2l_crtc(crtc);
> > > > > > > +
> > > > > > > +	rcrtc->vblank_enable = false; }
> > > > > >
> > > > > > You should enable / disable your interrupts here
> > > > >
> > > > > We don't have dedicated vblank IRQ for enabling/disabling vblank.
> > > > >
> > > > > vblank is handled by vspd.
> > > > >
> > > > > vspd is directly rendering images to display,
> > > > > rcar_du_crtc_finish_page_flip() and drm_crtc_handle_vblank()
> > > > > called in vspd's pageflip context.
> > > > >
> > > > > See rzg2l_du_vsp_complete()in rzg2l_du_vsp.c
> > > >
> > > > Sorry, I couldn't really get how the interrupt flow / vblank
> > > > reporting is going to work. Could you explain it a bit more?
> > >
> > > We just need to handle vertical blanking in the VSP frame end handler.
> > > See the code below.
> > >
> > > static void rzg2l_du_vsp_complete(void *private, unsigned int status,
> > > u32 crc) {
> > > 	struct rzg2l_du_crtc *crtc = private;
> > >
> > > 	if (crtc->vblank_enable)
> > > 		drm_crtc_handle_vblank(&crtc->crtc);
> > >
> > > 	if (status & VSP1_DU_STATUS_COMPLETE)
> > > 		rzg2l_du_crtc_finish_page_flip(crtc);
> > >
> > > 	drm_crtc_add_crc_entry(&crtc->crtc, false, 0, &crc); }
> > 
> > Then we're back to the same question :)
> > 
> > Why can't you mask the frame end interrupt?
> 
> We are masking interrupts.
> 
> [   70.639139] #######rzg2l_du_crtc_disable_vblank#######
> [   70.650243] #########rzg2l_du_vsp_disable ############
> [   70.652003] ########## vsp1_wpf_stop###
> 
> Unmask is,
> 
> [ 176.354520] #######rzg2l_du_crtc_enable_vblank#######
> [  176.354922] #########rzg2l_du_vsp_atomic_flush ############
> [  176.355198] ########## wpf_configure_stream###

Sorry, my question was why aren't you unmasking and masking them in the
enable/disable_vblank hooks of the CRTC.

Maxime
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