Independent clone mode
Barry Song
21cnbao at gmail.com
Wed Jul 31 21:43:30 UTC 2019
zou lan <nancy.lan.zou at gmail.com> 于2019年8月1日周四 上午3:40写道：
>
> Hi Barry
>
> May I ask if the overlay path is considered for the views between cloned outputs? For example, one view in this output could go through overlay, but in other
> cloned output, it can't. Or only using gpu composition for all cloned outputs?
for this case, i suggest you don't use overlay.
>
> Thank you!
>
> Best Regards
> Nancy
>
> Barry Song <21cnbao at gmail.com> 于2019年7月31日周三 上午5:48写道：
>>
>> Pekka Paalanen <ppaalanen at gmail.com> 于2019年7月27日周六 下午8:20写道：
>> >
>> > On Fri, 26 Jul 2019 08:58:42 +1200
>> > Barry Song <21cnbao at gmail.com> wrote:
>> >
>> > > Pekka Paalanen <ppaalanen at gmail.com> 于2019年7月26日周五 上午3:30写道：
>> > > >
>> > > > On Thu, 25 Jul 2019 13:00:55 +1200
>> > > > Barry Song <21cnbao at gmail.com> wrote:
>> > > >
>> > > > > Pekka Paalanen <ppaalanen at gmail.com> 于2019年7月24日周三 下午8:10写道：
>> > > > > >
>> > > > > > On Wed, 24 Jul 2019 13:22:43 +0800
>> > > > > > zou lan <nancy.lan.zou at gmail.com> wrote:
>> > > > > >
>> > > > > > > Hi pekka
>> > > > > > >
>> > > > > > > I see the clone mode is supported from this commit message.
>> > > > > > > https://patchwork.freedesktop.org/patch/227970/
>> > > > > > >
>> > > > > > > I also see the message "Independent CRTC clone mode cannot be supported
>> > > > > > > until output layout logic is moved from libweston into the frontend and
>> > > > > > > libweston's damage tracking issues stemming from overlapping outputs are
>> > > > > > > solved".
>> > > > > > >
>> > > > > > > I want to ask is independent CRTC clone mode already supported in Weston 6
>> > > > > > > or 7? If not,
>> > > > > > > is there a plan to support it?
>> > > > > >
>> > > > > > Hi,
>> > > > > >
>> > > > > > no, that commit message is still accurate. I don't know of any
>> > > > > > plans to work on independent CRTC clone mode.
>> > > > >
>> > > > > Pekka,
>> > > > > any possible workaround do you know to support independent crtc clone
>> > > > > within weston? right now it is very important product feature.
>> > > > > for example, force weston to identify only one screen, and sync copy
>> > > > > the screen to 2nd screen and call the drm api of 2nd screen?
>> > > >
>> > > > Hi,
>> > > >
>> > > > you could hack it up to do that, but it would be in no way an
>> > > > upstreamable solution. It would also hurt display timings because
>> > > > every repaint would have to wait for both monitors to refresh. Or,
>> > > > all but one monitor would tear.
>> > > >
>> > > > A simpler hack would be to create overlapping outputs and
>> > > > force them repaint fully on every refresh instead of repainting
>> > > > only the damage. That's not upstreamable either, but the damage
>> > > > could be hacked with probably a one-liner.
>> > >
>> > > Hi Pekka,
>> > > Thanks. even though i have seen many times that damage tracking of
>> > > overlapping outputs is the main cause stopping weston from supporting
>> > > full clone mode, i haven't fully understood what is overlapping
>> > > outputs in weston and found the code related with overlapping output,
>> > > would you like to point out some code path so that i can begin to do
>> > > some work on it? pls forgive me if you think the question is just
>> > > stupid.
>> >
>> > Hi,
>> >
>>
>>
>> i made a very great progress to hack weston to support clone mode in
>> the direction you pointed out.
>>
>> it works very well without any tearing.
>>
>> > what I suggested is not about code for overlapping outputs at all.
>> > I'm simply suggesting to hack e.g. weston_output_repaint() or
>> > something to ignore the accumulated damage and use full damage
>> > instead. I can't tell you exactly what and where without doing it
>> > myself first, which I cannot do at the moment.
>>
>> hacked by:
>>
>> @@ -2406,13 +2406,20 @@ weston_output_repaint(struct weston_output
>> *output, void *repaint_data)
>> }
>> }
>>
>> - compositor_accumulate_damage(ec);
>> + if (!output->external) {
>> + compositor_accumulate_damage(ec);
>>
>> - pixman_region32_init(&output_damage);
>> - pixman_region32_intersect(&output_damage,
>> - &ec->primary_plane.damage, &output->region);
>> - pixman_region32_subtract(&output_damage,
>> - &output_damage, &ec->primary_plane.clip);
>> + pixman_region32_init(&output_damage);
>> + pixman_region32_intersect(&output_damage,
>> + &ec->primary_plane.damage, &output->region);
>> + pixman_region32_subtract(&output_damage,
>> + &output_damage, &ec->primary_plane.clip);
>> + } else {
>> + /** From Pekka Paalanen: the damage could be hacked
>> with probably
>> + * a one-liner, ignore the accumulated damage and use
>> full damage
>> + */
>> + output_damage = output->region;
>> + }
>>
>>
>> >
>> > The other catch is to actually configure two weston_outputs to
>> > cover the same area of the desktop. I'm not sure if the existing
>> > libweston API is sufficient for that, but it certainly has not been
>> > designed for that. Again, I cannot tell you exactly, sorry.
>> >
>>
>> hacked simply by making the coordinates to 0:
>>
>> @@ -5706,8 +5713,9 @@ weston_output_enable(struct weston_output *output)
>> iterator = container_of(c->output_list.prev,
>> struct weston_output, link);
>>
>> + /** For clone mode, the coordinates of all displays will overlap */
>> if (!wl_list_empty(&c->output_list))
>> - x = iterator->x + iterator->width;
>> + x = (c->clone_mode ? 0 : iterator->x + iterator->width);
>>
>> and weston_view_assign_output() will get right output_mask.
>>
>> static void
>> weston_view_assign_output(struct weston_view *ev)
>> {
>> ...
>> wl_list_for_each(output, &ec->output_list, link) {
>> pixman_region32_intersect(®ion,
>> &ev->transform.boundingbox,
>> &output->region);
>>
>> e = pixman_region32_extents(®ion);
>> area = (e->x2 - e->x1) * (e->y2 - e->y1);
>>
>> if (area > 0)
>> mask |= 1u << output->id;
>>
>> ...
>> }
>>
>> ev->output_mask = mask;
>> }
>>
>> For example, suppose the extension mode is working, we have two 1080p displays.
>> (10, 10) will make output_mask=1, and (1930, 10) will make output_mask=2;
>> but in clone mode, (10, 10) will make output_mask=3, and (1930, 10) will make
>> output_mask=0;
>>
>> > Maybe weston_output_move or such would be enough? I'm not sure.
>> > Right now the layout code is hardcoded and hidden inside libweston,
>> > and you need to overwrite its outcome.
>>
>> since so many people are asking for clone mode in weston. would this
>> hacking version be accepted as an initial patch to support independent
>> clone?
>> if so, i will work on preparing a patch to send.
>>
>> >
>> >
>> > Thanks,
>> > pq
>>
>> -barry
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