Subject: Re: [PATCH v3 06/14] Documentation: drm/bridge: add document for
 analogix_dp
To: Thierry Reding <treding@nvidia.com>, Rob Herring <robherring2@gmail.com>
References: <1439995728-18046-1-git-send-email-ykk@rock-chips.com>
 <1439995834-18363-1-git-send-email-ykk@rock-chips.com>
 <CAL_JsqLz+8RtBucctUj4euXZ3Ac0DvB52N9ONpAerh5T9BiTJg@mail.gmail.com>
 <20150825091534.GB14034@ulmo.nvidia.com>
Cc: Heiko Stuebner <heiko@sntech.de>, Jingoo Han <jingoohan1@gmail.com>,
        Fabio Estevam <fabio.estevam@freescale.com>,
        Inki Dae <inki.dae@samsung.com>, Joe Perches <joe@perches.com>,
        Russell King <rmk+kernel@arm.linux.org.uk>,
        Sean Paul <seanpaul@google.com>, Takashi Iwai <tiwai@suse.de>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        Andrzej Hajda <a.hajda@samsung.com>,
        Gustavo Padovan <gustavo.padovan@collabora.co.uk>,
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        Kishon Vijay Abraham I <kishon@ti.com>,
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        Pawel Moll <pawel.moll@arm.com>,
        Ian Campbell <ijc+devicetree@hellion.org.uk>,
        Doug Anderson <dianders@google.com>, Rob Herring <robh+dt@kernel.org>,
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	<linux-arm-kernel@lists.infradead.org>,
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        Andy Yan <andy.yan@rock-chips.com>
From: Yakir Yang <ykk@rock-chips.com>
Message-ID: <55DC3742.2070308@rock-chips.com>
Date: Tue, 25 Aug 2015 17:37:06 +0800
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Hi Thierry,

在 2015/8/25 17:15, Thierry Reding 写道:
> On Sun, Aug 23, 2015 at 06:23:14PM -0500, Rob Herring wrote:
>> On Wed, Aug 19, 2015 at 9:50 AM, Yakir Yang <ykk@rock-chips.com> wrote:
> [...]
>>> +       -analogix,link-rate:
>>> +               max link rate supported by the eDP controller.
>>> +                       LINK_RATE_1_62GBPS = 0x6, LINK_RATE_2_70GBPS = 0x0A,
>>> +                       LINK_RATE_5_40GBPS = 0x14
>> Same here. I'd rather see something like "link-rate-mbps" and use the
>> actual rate.
> There is no need whatsoever to hard-code this in DT. (e)DP provides the
> means to detect what rate the link supports and the specification
> provides guidance on how to select an appropriate one.

Hmm... could you share more about this :-)

I only find that drm_dp_link_probe() could get the panel link-rate and
num-lanes by reading the DP_DPCD_REV messag.

I don't found there are some guidance to help select the approriate one.
Beside this DT prop just indicate the max eDP controller link-rate & lanes
support, how could eDP detect them automatically?

- Yakir

>>> +       -analogix,lane-count:
>>> +               max number of lanes supported by the eDP contoller.
>>> +                       LANE_COUNT1 = 1, LANE_COUNT2 = 2, LANE_COUNT4 = 4
>> And drop the vendor prefix here.
> Same as for the link rate.
>
> Thierry


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