Re: [PATCH v2 0/6] eDP: Support probing eDP panels dynamically instead of hardcoding

From: Doug Anderson <dianders@chromium.org>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: Thierry Reding <thierry.reding@gmail.com>,
	Rob Herring <robh+dt@kernel.org>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	Daniel Vetter <daniel@ffwll.ch>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>, David Airlie <airlied@linux.ie>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Maxime Ripard <mripard@kernel.org>,
	Steev Klimaszewski <steev@kali.org>,
	Linus W <linus.walleij@linaro.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 0/6] eDP: Support probing eDP panels dynamically instead of hardcoding
Date: Thu, 12 Aug 2021 09:00:15 -0700	[thread overview]
Message-ID: <CAD=FV=UiATFdiYbrAtinmu3BwO=XoOLaWBkypxRwm+GqfQEhyg@mail.gmail.com> (raw)
In-Reply-To: <YRTsFNTn/T8fLxyB@ravnborg.org>

Hi,

On Thu, Aug 12, 2021 at 2:38 AM Sam Ravnborg <sam@ravnborg.org> wrote:
>
> Hi Doug,
> On Mon, Aug 09, 2021 at 03:18:03PM -0700, Doug Anderson wrote:
> > Hi,
> >
> > On Tue, Aug 3, 2021 at 1:41 PM Sam Ravnborg <sam@ravnborg.org> wrote:
> > >
> > > Hi Douglas,
> > >
> > > On Fri, Jul 30, 2021 at 02:26:19PM -0700, Douglas Anderson wrote:
> > > > The goal of this patch series is to move away from hardcoding exact
> > > > eDP panels in device tree files. As discussed in the various patches
> > > > in this series (I'm not repeating everything here), most eDP panels
> > > > are 99% probable and we can get that last 1% by allowing two "power
> > > > up" delays to be specified in the device tree file and then using the
> > > > panel ID (found in the EDID) to look up additional power sequencing
> > > > delays for the panel.
> > >
> > > Have you considered a new driver for edp panels?
> > > panel-edp.c?
> > >
> > > There will be some duplicate code from pnale-simple - but the same can
> > > be said by the other panel drivers too.
> > > In the end I think it is better to separate them so we end up with two
> > > less complex panel drivers rather than one do-it-all panel driver.
> > >
> > > I have not looked in detail how this would look like, but my first
> > > impression is that we should split it out.
> >
> > I certainly could, but my argument against it is that really it's the
> > exact same set of eDP panels that would be supported by both drivers.
>
> The idea was to move all eDP panels to the new driver.
>
> My hope it that we can make panel-simple handle a more more narrow set
> of panels. eDP capable displays are IMO not simple panels.

Ah! OK, this makes sense. I can work on this, though it might be a
short while before I can. I think moving all eDP panels out of
panel-simple.c to something like panel-simple-edp.c makes sense. It
will be a patch that will be very hard to cherry-pick anywhere since
it will conflict with everything but it should be doable.

> Likewise DSI capable panels could also be pulled out of panel-simple.

At the moment I haven't done much with DSI panels so I might leave
them in panel-simple for now. I'll evaluate to see how nasty it would
be for me to try this.

> This would continue to duplicate some code - but we have a lot of
> duplicated code across the various panels and the best way forward
> would be to implement more helpers that can be used by the drivers.
>
>         Sam - who is trying to recover form the deadly man flu...

Feel better!

-Doug