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Message-ID: <bb5b776c-f1dd-f53e-079c-8048af2e73f1@starfivetech.com>
Date:   Wed, 18 Oct 2023 10:37:29 +0800
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Subject: Re: [PATCH v10 0/8] Add StarFive Camera Subsystem driver
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To:     Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Robert Foss <rfoss@kernel.org>,
        Todor Tomov <todor.too@gmail.com>,
        <bryan.odonoghue@linaro.org>, Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>
CC:     <linux-media@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <devicetree@vger.kernel.org>, <linux-staging@lists.linux.dev>,
        <changhuang.liang@starfivetech.com>
References: <20231008085154.6757-1-jack.zhu@starfivetech.com>
 <98297bfc-ab81-4bb5-acc3-619fdf879276@xs4all.nl>
From:   Jack Zhu <jack.zhu@starfivetech.com>
In-Reply-To: <98297bfc-ab81-4bb5-acc3-619fdf879276@xs4all.nl>
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Hi Hans,

Thank you for your comments.

On 2023/10/16 19:40, Hans Verkuil wrote:
> Hi Jack,
> 
> On 08/10/2023 10:51, Jack Zhu wrote:
>> Hi,
>> 
>> This series is the v10 series that attempts to support the Camera Subsystem
>> found on StarFive JH7110 SoC.
>> 
>> This series is based on top of the master branch of media_stage repository,
>> which is tested with a v4l2-compliance compiled from the git repo
>> (git://linuxtv.org/v4l-utils.git).
> 
> I get one smatch warning:
> 
> drivers/staging/media/starfive/camss/stf-isp.c:122 isp_enum_mbus_code() warn: unsigned 'code->index' is never less than zero.
> 
> And I also notice that there is no TODO file: staging drivers should have a
> TODO file explaining what needs to be done to get them out of staging.
> 
> I'm curious to know that as well :-)
> 
> It looks like there is a lot of additional development that can be done, since
> most of the ISP parameters appear to be hardcoded.
> 
> I also notice something weird in the compliance test output for v4l-subdev0 vs
> v4l-subdev1:
> 
>> Compliance test for starfive-camss device /dev/v4l-subdev0:
>> 
>> Driver Info:
>> 	Driver version   : 6.6.0
>> 	Capabilities     : 0x00000000
>> Media Driver Info:
>> 	Driver name      : starfive-camss
>> 	Model            : Starfive Camera Subsystem
>> 	Serial           : 
>> 	Bus info         : platform:19840000.camss
>> 	Media version    : 6.6.0
>> 	Hardware revision: 0x00000000 (0)
>> 	Driver version   : 6.6.0
>> Interface Info:
>> 	ID               : 0x0300001c
>> 	Type             : V4L Sub-Device
>> Entity Info:
>> 	ID               : 0x00000001 (1)
>> 	Name             : stf_isp
>> 	Function         : Image Signal Processor
>> 	Pad 0x01000002   : 0: Sink
>> 	  Link 0x02000014: from remote pad 0x1000010 of entity 'cdns_csi2rx.19800000.csi-bridge' (Video Interface Bridge): Data, Enabled
>> 	Pad 0x01000003   : 1: Source
>> 	  Link 0x0200000c: to remote pad 0x1000009 of entity 'capture_yuv' (V4L2 I/O): Data, Enabled
> 
> Here it shows the Media Driver Info for v4l-subdev0.
> 
> <snip>
> 
>> --------------------------------------------------------------------------------
>> Compliance test for device /dev/v4l-subdev1:
>> 
>> Driver Info:
>> 	Driver version   : 6.6.0
>> 	Capabilities     : 0x00000000
> 
> But this does not appear for v4l-subdev1.
> 
> I can't really tell why it doesn't show that. Can you debug a little bit?
> The code is in v4l2-compliance.cpp, line 1086:
> 
> ent_id = mi_media_info_for_fd(media_fd, node.g_fd(), &is_invalid, &node.function);
> 
> The mi_media_info_for_fd() function calls ioctl(media_fd, MEDIA_IOC_DEVICE_INFO, &mdinfo),
> and that fails for some reason. It could be that media_fd is invalid (would be weird).
> 
> This could well be a v4l2-compliance bug that you hit with this driver.
> 

On the test board, /dev/v4l-subdev1 is imx219, and the corresponding directory is
/sys/dev/char/81:3/device. Media0 does not exist in this directory. Therefore, the media_fd
obtained through mi_get_media_fd(node.g_fd(), node.bus_info) is invalid.

I don't know why media0 does not exist in /sys/dev/char/81:3/device?

-- 
Regards,

Jack Zhu