Re: [PATCH v3 1/1] drm: bridge: ti-sn65dsi83: Fix DSI mode flags for stable LVDS output

[Francesco Dolcini <francesco@dolcini.it>]

+regression list

Hello all,

On Thu, Oct 29, 2026 at 04:50:39PM +0100, Ernest Van Hoecke wrote:
> On Sat, Oct 24, 2026 at 11:54:05AM +0200, Francesco Dolcini wrote:
> > On Wed, Sep 09, 2026 at 03:30:53PM +0200, Luca Ceresoli wrote:
> > > On Fri Sep 4, 2026 at 2:02 PM CEST, Ernest Van Hoecke wrote:
> > > >> > Also, from our testing, when using:
> > > >> >
> > > >> > dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST |
> > > >> >           MIPI_DSI_MODE_VIDEO_NO_HSA | MIPI_DSI_MODE_NO_EOT_PACKET;
> > > >> >
> > > >> > we are not able to get display output.
> > > >>
> > > >> This is the case for the panel I worked on as well. In the practice we both
> > > >> observe that non-burst mode is what fixes the panel, but there is no clear
> > > >> explanation of the reason in the docs (that's what I hope to discover from
> > > >> TI).
> > > >>
> > > > I am testing a DSI panel on our Verdin iMX8MP module, and noticed that
> > > > this caused a regression.
> > 
> > [...]
> > 
> > > > I think we'll need to either revert this and later apply both together
> > > > when ready, or apply the second patch now as well. Right now, it broke
> > > > the DSI panel behind a TI sn65dsi83 bridge on v7.3-rc1.
> > > 
> > > Reverting is surely the last resort. If you can answer the above questions
> > > it would be good, maybe we find out reverting is not necessary, and worst
> > > case we'll revert with better understanding on what went wrong, and maybe
> > > come up with a new fix that doesn't regress.
> > 
> > What's the status of this regression?
> 
> I still need to test and look into this, that will happen either in
> December as I'm off in November, or by someone else in the team. Sorry
> for the delay.

Luca: I think we should revert this for the moment, the regression is
real, and I do not see an immediate way forward.

#regzbot ^introduced: 4af021a97773
#regzbot title: drm: bridge: ti-sn65dsi83: display broken on Verdin iMX8MP after enabling HFP/HBP
#regzbot link: https://lore.kernel.org/all/3hfae2i2i2toxbo7hg2if6pztaswgnfj65xfm2c4ofljc6jhua@slaqoewn4mxq/

Francesco