Re: [PATCH v5 3/4] drm/bridge: Introduce LT9611 DSI to HDMI bridge

From: Vinod Koul <vkoul@kernel.org>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: devicetree@vger.kernel.org,
	Jernej Skrabec <jernej.skrabec@siol.net>,
	Neil Armstrong <narmstrong@baylibre.com>,
	David Airlie <airlied@linux.ie>,
	linux-arm-msm@vger.kernel.org, Jonas Karlman <jonas@kwiboo.se>,
	Emil Velikov <emil.l.velikov@gmail.com>,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Andrzej Hajda <a.hajda@samsung.com>,
	Rob Herring <robh+dt@kernel.org>,
	Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Subject: Re: [PATCH v5 3/4] drm/bridge: Introduce LT9611 DSI to HDMI bridge
Date: Thu, 23 Jul 2020 17:40:34 +0530	[thread overview]
Message-ID: <20200723121034.GA12965@vkoul-mobl> (raw)
In-Reply-To: <20200723113912.GA535520@ravnborg.org>

On 23-07-20, 13:39, Sam Ravnborg wrote:
> On Thu, Jul 23, 2020 at 04:11:51PM +0530, Vinod Koul wrote:
> > Hi Sam, Laurent,
> > 
> > On 22-07-20, 16:14, Laurent Pinchart wrote:
> > > > > +static int lt9611_bridge_attach(struct drm_bridge *bridge,
> > > > > +				enum drm_bridge_attach_flags flags)
> > > > > +{
> > > > > +	struct lt9611 *lt9611 = bridge_to_lt9611(bridge);
> > > > > +	int ret;
> > > > > +
> > > > > +	if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)) {
> > > > > +		dev_err(lt9611->dev, "Fix bridge driver to make connector optional!");
> > > > > +		return -EINVAL;
> > > > > +	}
> > > >
> > > > This should say that the display driver should be fixed.
> > > > If a display driver expects this bridge to create the connector
> > > > it would not work.
> > > 
> > > Actually, for new bridge drivers, connector creation should be optional
> > > from the start. We don't want a failure in that case, the feature should
> > > be implemented.
> > 
> > Yes this is causing issues for me now !. The patch 4/4 adds support in
> > msm/dsi but causes regression on qualcomm laptops with ti-sn65dsi86 eDP
> > bridge. I tried to fix that up with changes like Laurent has done for
> > adv7511, but it hasnt worked yet for me (remote debug of this is bit
> > painful)
> > 
> > So I am going to drop patch 4 from this series and add support for both
> > DRM_BRIDGE_ATTACH_NO_CONNECTOR set and cleared (like we have in adv7511)
> > so that it can work in both cases, while I fix all bridge uses of
> > msm/dsi and then we can drop these. Does that sound okay to you folks?
> Yes, sounds like a good plan.
> Only when all display drivers are migrated over can we drop all the
> workarounds in the bridge drivers.
> I had hoped all users of this bridge was converted - alas that was not
> the case.

Thanks, I will send updated patchset fixing the nits and supporting both
the cases and will drop msm/dsi patch for now

-- 
~Vinod
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