[PATCH] drm/mediatek: reduce the hbp and hfp for phy timing

[Enric Balletbo Serra]

Hi all,

Missatge de Hsin-Yi Wang <hsinyi at chromium.org> del dia dl., 16 de des.
2019 a les 3:42:
>
> On Fri, Dec 13, 2019 at 9:52 AM Jitao Shi <jitao.shi at mediatek.com> wrote:
> >
> > There are some extra data transfer in dsi.
> > ex. LPX, hs_prepare, hs_zero, hs_exit and the sof/eof of dsi packet.
> > This signal will enlarge the line time. So the real frame on dsi bus
> > will be lower than calc by video timing.
> >
> > So dsi driver reduces the hbp and hfp to keep the line time.
> >

This patch not only reduces the hbp and hfp for phy timing, it also
fixes an actual issue for MT8173 boards (i.e. Acer Chromebook R 13)
which is that the display is not working anymore (black screen) after
7a5bc4e22ecfd74dc3662342beaa909770a3b786 "drm/mediatek: change the dsi
phytiming calculate method". So the patch is probably missing a:

Fixes: 7a5bc4e22ecf ("drm/mediatek: change the dsi phytiming calculate method")

And would be nice to have this patch applied for 5.5

> > Signed-off-by: Jitao Shi <jitao.shi at mediatek.com>
> Tested-by: Hsin-Yi Wang <hsinyi at chromium.org>

If it helps, you can also add my

Tested-by: Enric Balletbo i Serra <enric.balletbo at collabora.com>

Thanks,
 Enric

> > ---
>
> Tested on mt8183 and mt8173
>
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