On Wed, Feb 28, 2024 at 10:02:13AM +0200, Stanislav Lisovskiy wrote: > Currently we can't change MBUS join status without doing a modeset, > because we are lacking mechanism to synchronize those with vblank. > However then this means that we can't do a fastset, if there is a need > to change MBUS join state. Fix that by implementing such change. > We already call correspondent check and update at pre_plane dbuf update, > so the only thing left is to have a non-modeset version of that. > If active pipes stay the same then fastset is possible and only MBUS > join state/ddb allocation updates would be committed. > > v2: Implement additional changes according to BSpec. > Vblank wait is needed after MBus/Dbuf programming in case if > no modeset is done and we are switching from single to multiple > displays, i.e mbus join state switches from "joined" to "non-joined" > state. Otherwise vblank wait is not needed according to spec. > > v3: Split mbus and dbox programming into to pre/post plane update parts, > how it should be done according to BSpec. > > v4: - Place "single display to multiple displays scenario" MBUS/DBOX programming > after DDB reallocation, but before crtc enabling(that is where is has > to be according to spec). > - Check if crtc is still active, not only the old state. > - Do a vblank wait if MBUX DBOX register was modified. > - And of course do vblank wait only if crtc was active. > - Do vblank wait only if we are not doing a modeset, if we are doing > something before *commit_modeset_enables, because all crtcs might be > disabled at this moment, so we will get WARN if try waiting for vblank > then. > - Still getting FIFO underrun so try waiting for vblank in pre_plane update > as well. > - Write also pipe that we need to sync with to MBUS_CTL register. > > v5: - Do vblank wait only for the first pipe, if mbus is joined > - Check also if new/old_dbuf_state is not NULL, before getting single pipe > and active pipes. > > Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@xxxxxxxxx> Thank you for this patch, Stanislav! We tested it on a MTL-U based Chromebook (Screebo), using different configurations (eDP, eDP + HDMI, HDMI, etc.), and it worked well -- joined the mbus + no visual issues or i915 errors. Tested-by: Paz Zcharya <pazz@xxxxxxxxxxxx> Just a small note, checkpatch.pl is complaining about a few things. I assume you probably saw it, but flagging just in case.
