From: Thierry Reding <thierry.reding@gmail.com>
To: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Sam Ravnborg <sam@ravnborg.org>,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Maxime Ripard <mripard@kernel.org>,
Thomas Zimmermann <tzimmermann@suse.de>,
David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH] drm/panel: Make backlight attachment lazy
Date: Tue, 8 Dec 2020 13:47:56 +0100 [thread overview]
Message-ID: <X891/LvEJT1bLtjH@ulmo> (raw)
In-Reply-To: <20201208044446.973238-1-bjorn.andersson@linaro.org>
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On Mon, Dec 07, 2020 at 10:44:46PM -0600, Bjorn Andersson wrote:
> Some bridge chips, such as the TI SN65DSI86 DSI/eDP bridge, provides
> means of generating a PWM signal for backlight control of the attached
> panel. The provided PWM chip is typically controlled by the
> pwm-backlight driver, which if tied to the panel will provide DPMS.
>
> But with the current implementation the panel will refuse to probe
> because the bridge driver has yet to probe and register the PWM chip,
> and the bridge driver will refuse to probe because it's unable to find
> the panel.
What you're describing is basically a circular dependency. Can't we get
rid of that in some other way? Why exactly does the bridge driver refuse
to probe if the panel can't be found?
In other words, I see how the bridge would /use/ the panel in that it
forward a video stream to it. But how does the panel /use/ the bridge?
Thierry
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next prev parent reply other threads:[~2020-12-08 12:48 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-08 4:44 [RFC PATCH] drm/panel: Make backlight attachment lazy Bjorn Andersson
2020-12-08 5:48 ` Sam Ravnborg
2020-12-08 21:39 ` Bjorn Andersson
2020-12-08 12:47 ` Thierry Reding [this message]
2020-12-08 22:02 ` Bjorn Andersson
2020-12-08 23:52 ` Daniel Vetter
2020-12-09 20:28 ` Bjorn Andersson
2020-12-10 10:15 ` Daniel Vetter
2020-12-10 16:44 ` Thierry Reding
2020-12-10 16:50 ` Daniel Vetter
2020-12-10 17:18 ` Thierry Reding
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