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Date:   Sat, 9 Apr 2022 12:25:30 +0800
From:   Enze Li <lienze@kylinos.cn>
To:     Jens Axboe <axboe@kernel.dk>
Cc:     phil@philpotter.co.uk, linux-kernel@vger.kernel.org,
        linux-block@vger.kernel.org
Subject: Re: [PATCH] cdrom: do not print info list when there is no cdrom
 device
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References: <20220408084221.1681592-1-lienze@kylinos.cn>
        <25390602-cfa0-dba3-bfbc-a35ed6b44bcf@kernel.dk>
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On Fri, 8 Apr 2022 06:34:04 -0600
Jens Axboe <axboe@kernel.dk> wrote:

> On 4/8/22 2:42 AM, Enze Li wrote:
> > There is no need to print a list of cdrom entries with blank info
> > when no cdrom device exists.  With this patch applied, we get:
> > 
> > ================================================
> > $ cat /proc/sys/dev/cdrom/info
> > CD-ROM information, Id:cdrom.c 3.20 2003/12/17
> > 
> > No device found.
> > 
> > ================================================  

Hi Jens,

Thanks for your review.

> 
> And what did we get before?

Without the patch, we get:

================================================
$ cat /proc/sys/dev/cdrom/info
CD-ROM information, Id: cdrom.c 3.20 2003/12/17

drive name:	
drive speed:	
drive # of slots:
Can close tray:	
Can open tray:	
Can lock tray:	
Can change speed:
Can select disk:
Can read multisession:
Can read MCN:	
Reports media changed:
Can play audio:	
Can write CD-R:	
Can write CD-RW:
Can read DVD:	
Can write DVD-R:
Can write DVD-RAM:
Can read MRW:	
Can write MRW:	
Can write RAM:	


================================================

> 
> Will this potentially break applications that parse it?
> 

I dunno, is there any way to confirm this thing?  And if this is really
a possibility, does it mean that we cannot make changes?

BTW, could you pls help review the following patch?  I forgot to cc you
and linux-block@list. :)
https://lore.kernel.org/lkml/20220406090337.1116708-1-lienze@kylinos.cn/

Thanks,
Enze