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Message-ID: <ceee318c-1d57-4b3d-9754-1a9ee53fc4e2@collabora.com>
Date: Fri, 1 Mar 2024 10:37:34 +0100
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Subject: Re: [PATCH v2 9/9] drm/panel: truly-nt35597: Don't log an error when
 DSI host can't be found
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To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: =?UTF-8?B?TsOtY29sYXMgRi4gUi4gQS4gUHJhZG8=?= <nfraprado@collabora.com>,
 Andrzej Hajda <andrzej.hajda@intel.com>,
 Neil Armstrong <neil.armstrong@linaro.org>, Robert Foss <rfoss@kernel.org>,
 Jonas Karlman <jonas@kwiboo.se>, Jernej Skrabec <jernej.skrabec@gmail.com>,
 Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
 Maxime Ripard <mripard@kernel.org>, Thomas Zimmermann <tzimmermann@suse.de>,
 David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
 owen <qwt9588@gmail.com>, Jagan Teki <jagan@amarulasolutions.com>,
 Marek Vasut <marex@denx.de>, Adrien Grassein <adrien.grassein@gmail.com>,
 Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
 Sam Ravnborg <sam@ravnborg.org>, Bjorn Andersson <andersson@kernel.org>,
 Vinod Koul <vkoul@kernel.org>, Dmitry Baryshkov
 <dmitry.baryshkov@linaro.org>, Vinay Simha BN <simhavcs@gmail.com>,
 Christopher Vollo <chris@renewoutreach.org>,
 Jessica Zhang <quic_jesszhan@quicinc.com>,
 Marijn Suijten <marijn.suijten@somainline.org>,
 AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>,
 kernel@collabora.com, dri-devel@lists.freedesktop.org,
 linux-kernel@vger.kernel.org
References: <20240229-anx7625-defer-log-no-dsi-host-v2-0-00506941049a@collabora.com>
 <20240229-anx7625-defer-log-no-dsi-host-v2-9-00506941049a@collabora.com>
 <20240301063020.GL30889@pendragon.ideasonboard.com>
 <fc12dbc9-5c0b-4bff-8754-5b9a5f7b0e12@collabora.com>
 <20240301085624.GC30104@pendragon.ideasonboard.com>
From: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
In-Reply-To: <20240301085624.GC30104@pendragon.ideasonboard.com>
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Il 01/03/24 09:56, Laurent Pinchart ha scritto:
> On Fri, Mar 01, 2024 at 09:44:36AM +0100, AngeloGioacchino Del Regno wrote:
>> Il 01/03/24 07:30, Laurent Pinchart ha scritto:
>>> On Thu, Feb 29, 2024 at 07:12:15PM -0500, Nícolas F. R. A. Prado wrote:
>>>> Given that failing to find a DSI host causes the driver to defer probe,
>>>> make use of dev_err_probe() to log the reason. This makes the defer
>>>> probe reason available and avoids alerting userspace about something
>>>> that is not necessarily an error.
>>>>
>>>> Suggested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
>>>> Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
>>>> ---
>>>>    drivers/gpu/drm/panel/panel-truly-nt35597.c | 6 ++----
>>>>    1 file changed, 2 insertions(+), 4 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/panel/panel-truly-nt35597.c b/drivers/gpu/drm/panel/panel-truly-nt35597.c
>>>> index b73448cf349d..d447db912a61 100644
>>>> --- a/drivers/gpu/drm/panel/panel-truly-nt35597.c
>>>> +++ b/drivers/gpu/drm/panel/panel-truly-nt35597.c
>>>> @@ -550,10 +550,8 @@ static int truly_nt35597_probe(struct mipi_dsi_device *dsi)
>>>>    
>>>>    	dsi1_host = of_find_mipi_dsi_host_by_node(dsi1);
>>>>    	of_node_put(dsi1);
>>>> -	if (!dsi1_host) {
>>>> -		dev_err(dev, "failed to find dsi host\n");
>>>> -		return -EPROBE_DEFER;
>>>> -	}
>>>> +	if (!dsi1_host)
>>>> +		return dev_err_probe(dev, -EPROBE_DEFER, "failed to find dsi host\n");
>>>
>>> 		return dev_err_probe(dev, -EPROBE_DEFER,
>>> 				     "failed to find dsi host\n");
>>>
>>> With this addressed,
>>
>> I disagree. That's 87 columns, and the 80-col rule is long gone.
> 
> It's still a maintainer's preference. I soft-enforce it in drivers I
> maintain. In this case I'll let Neil decide, as he's listed as the
> maintainer for drivers/gpu/drm/panel/.
> 

Yes, that's right. Comes down to personal opinion.

Cheers

>> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
>>
>>> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>>>
>>>>    
>>>>    	/* register the second DSI device */
>>>>    	dsi1_device = mipi_dsi_device_register_full(dsi1_host, &info);
>