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From:   Brian Norris <briannorris@chromium.org>
Date:   Thu, 25 Jan 2018 14:51:00 -0800
Message-ID: <CA+ASDXOXBV0gUrKMb9W2M5EGLUBLjDp4L1qRhnyor04cnS7AsQ@mail.gmail.com>
Subject: Re: [PATCH v1 1/2] drm/bridge/synopsys: dsi: Fix dsi_host_transfer()
 return value
To:     Andrzej Hajda <a.hajda@samsung.com>
Cc:     Philippe CORNU <philippe.cornu@st.com>,
        Bhumika Goyal <bhumirks@gmail.com>,
        Alexandre TORGUE <alexandre.torgue@st.com>,
        David Airlie <airlied@linux.ie>,
        Linux Kernel <linux-kernel@vger.kernel.org>,
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        Yannick FERTRE <yannick.fertre@st.com>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@lists.infradead.org>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Ludovic BARRE <ludovic.barre@st.com>,
        Mickael REULIER <mickael.reulier@st.com>,
        Vincent ABRIOU <vincent.abriou@st.com>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        Thierry Reding <thierry.reding@gmail.com>
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On Thu, Jan 25, 2018 at 4:16 AM, Andrzej Hajda <a.hajda@samsung.com> wrote:
> On 24.01.2018 19:37, Brian Norris wrote:
>> With your current patch, you're returning the 'mipi_dsi_packet::size',
>> which is the sum of both TX and RX.
>
> I did not found docs saying mipi_dsi_packet::size is a sum of tx and rx.
> tx and rx packets are two different packets, so they do not sum up.
> But thanks for bringing it up, it shows docs are incomplete/misleading.

Ugh, I misread that again. No, mipi_dsi_packet::size is NOT claimed to
contain both TX and RX. It just says "size of the packet", and packet
clearly does not hold the RX data anyway. I don't know what's
happening to my reading comprehension...

But the mismatch on whether drivers implement these correctly and
whether any callers actually care about the documented semantics still
stands.

Brian