From: Philippe CORNU <philippe.cornu@st.com>
To: Brian Norris <briannorris@chromium.org>
Cc: "linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
"open list:ARM/Rockchip SoC..."
<linux-rockchip@lists.infradead.org>,
David Airlie <airlied@linux.ie>,
"Linux Kernel" <linux-kernel@vger.kernel.org>,
"dri-devel@lists.freedesktop.org"
<dri-devel@lists.freedesktop.org>,
Yannick FERTRE <yannick.fertre@st.com>,
Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
Ludovic BARRE <ludovic.barre@st.com>,
Mickael REULIER <mickael.reulier@st.com>,
"Vincent ABRIOU" <vincent.abriou@st.com>,
Bhumika Goyal <bhumirks@gmail.com>,
"Alexandre TORGUE" <alexandre.torgue@st.com>
Subject: Re: [PATCH v1 1/2] drm/bridge/synopsys: dsi: Fix dsi_host_transfer() return value
Date: Wed, 24 Jan 2018 13:33:54 +0000 [thread overview]
Message-ID: <4a1b0208-3187-2f08-69fe-ca3b77ee88a8@st.com> (raw)
In-Reply-To: <CA+ASDXNDpmVdARLCD-A6nfADgmomuscpwekb8M-j=MFJhpeC4Q@mail.gmail.com>
Hi Brian,
And many thanks for your review.
On 01/23/2018 10:38 PM, Brian Norris wrote:
> Hi Philippe,
>
> On Tue, Jan 23, 2018 at 6:26 AM, Philippe Cornu <philippe.cornu@st.com> wrote:
>> The dw_mipi_dsi_host_transfer() must return the number of
>> bytes transmitted/received on success instead of 0.
>
> I'm a little confused. As of the latest drm-misc-next I'm looking at,
> this still has conflicting documentation.
>
> For ->transfer():
>
> On success it shall return the number of bytes
> * transmitted for write packets or the number of bytes received for read
> * packets.
>
> While mipi_dsi_generic_read() says:
>
> * Return: The number of bytes successfully read or a negative error code on
> * failure.
>
> But it just returns the value that ->transfer() returns.
>
Not sure to follow you here: mipi_dsi_generic_read() will trig a dsi
generic read so it has to return "the number of bytes received for read
packets" as explained for the ->transfer() function... so it looks
"coherent"...
But maybe you want to point out something different?
> So I'm not sure whether the documentation is still wrong, or if the
> implementation is.
>
> Anyway, I guess maybe that isn't super-critical to *this* patch, since
> we don't have RX support yet...
>
The main reason why I want to "fix" this is because I do not want to
explain to our customers (writing dsi panel drivers) why we have a
different returned value compare to other platforms : )
>> Note: nb_bytes is introduced in this patch as it will be
>> re-used with the future dcs/generic dsi read feature.
>
> It feels like you could just wait to add that when you need it? It
> really feels trivial and useless right now :)
>
> Brian
>
Thanks, I agree, I will write & send a simpler version.
Philippe :-)
>>
>> Signed-off-by: Philippe Cornu <philippe.cornu@st.com>
>> ---
>> drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 10 ++++++++--
>> 1 file changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>> index f458798af788..096cf5e5bb30 100644
>> --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>> @@ -403,7 +403,7 @@ static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
>> {
>> struct dw_mipi_dsi *dsi = host_to_dsi(host);
>> struct mipi_dsi_packet packet;
>> - int ret;
>> + int ret, nb_bytes;
>>
>> ret = mipi_dsi_create_packet(&packet, msg);
>> if (ret) {
>> @@ -413,7 +413,13 @@ static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
>>
>> dw_mipi_message_config(dsi, msg);
>>
>> - return dw_mipi_dsi_write(dsi, &packet);
>> + ret = dw_mipi_dsi_write(dsi, &packet);
>> + if (ret)
>> + return ret;
>> +
>> + nb_bytes = packet.size;
>> +
>> + return nb_bytes;
>> }
>>
>> static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {
>> --
>> 2.15.1
>>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
next prev parent reply other threads:[~2018-01-24 13:34 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-23 14:26 [PATCH v1 0/2] drm/bridge/synopsys: dsi: Add fix & warning in dsi_host_transfer() Philippe Cornu
2018-01-23 14:26 ` [PATCH v1 1/2] drm/bridge/synopsys: dsi: Fix dsi_host_transfer() return value Philippe Cornu
2018-01-23 21:38 ` Brian Norris
2018-01-24 13:33 ` Philippe CORNU [this message]
2018-01-24 18:37 ` Brian Norris
2018-01-25 12:16 ` Andrzej Hajda
2018-01-25 22:51 ` Brian Norris
2018-01-23 14:26 ` [PATCH v1 2/2] drm/bridge/synopsys: dsi: Add a warning msg on dsi read operations Philippe Cornu
2018-01-23 21:28 ` Brian Norris
2018-01-24 13:22 ` Philippe CORNU
2018-01-24 18:14 ` Brian Norris
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