linux-kernel - Re: [PATCH 1/4] lib/hexdump.c: Allow 64 bytes per line

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Date:   Mon, 15 Apr 2019 11:02:32 +0200
From:   Petr Mladek <pmladek@...e.com>
To:     Alastair D'Silva <alastair@...ilva.org>
Cc:     'Jani Nikula' <jani.nikula@...ux.intel.com>,
        'Joonas Lahtinen' <joonas.lahtinen@...ux.intel.com>,
        'Rodrigo Vivi' <rodrigo.vivi@...el.com>,
        'David Airlie' <airlied@...ux.ie>,
        'Daniel Vetter' <daniel@...ll.ch>,
        'Karsten Keil' <isdn@...ux-pingi.de>,
        'Jassi Brar' <jassisinghbrar@...il.com>,
        'Tom Lendacky' <thomas.lendacky@....com>,
        "'David S. Miller'" <davem@...emloft.net>,
        'Jose Abreu' <Jose.Abreu@...opsys.com>,
        'Kalle Valo' <kvalo@...eaurora.org>,
        'Stanislaw Gruszka' <sgruszka@...hat.com>,
        'Benson Leung' <bleung@...omium.org>,
        'Enric Balletbo i Serra' <enric.balletbo@...labora.com>,
        "'James E.J. Bottomley'" <jejb@...ux.ibm.com>,
        "'Martin K. Petersen'" <martin.petersen@...cle.com>,
        'Greg Kroah-Hartman' <gregkh@...uxfoundation.org>,
        'Alexander Viro' <viro@...iv.linux.org.uk>,
        'Sergey Senozhatsky' <sergey.senozhatsky@...il.com>,
        'Steven Rostedt' <rostedt@...dmis.org>,
        'Andrew Morton' <akpm@...ux-foundation.org>,
        intel-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
        ath10k@...ts.infradead.org, linux-wireless@...r.kernel.org,
        linux-scsi@...r.kernel.org, linux-fbdev@...r.kernel.org,
        devel@...verdev.osuosl.org, linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH 1/4] lib/hexdump.c: Allow 64 bytes per line

On Sat 2019-04-13 09:22:05, Alastair D'Silva wrote:
> > -----Original Message-----
> > From: Petr Mladek <pmladek@...e.com>
> > Sent: Friday, 12 April 2019 11:48 PM
> > To: Alastair D'Silva <alastair@....ibm.com>
> > Cc: alastair@...ilva.org; Jani Nikula <jani.nikula@...ux.intel.com>;
> Joonas
> > Lahtinen <joonas.lahtinen@...ux.intel.com>; Rodrigo Vivi
> > <rodrigo.vivi@...el.com>; David Airlie <airlied@...ux.ie>; Daniel Vetter
> > <daniel@...ll.ch>; Karsten Keil <isdn@...ux-pingi.de>; Jassi Brar
> > <jassisinghbrar@...il.com>; Tom Lendacky <thomas.lendacky@....com>;
> > David S. Miller <davem@...emloft.net>; Jose Abreu
> > <Jose.Abreu@...opsys.com>; Kalle Valo <kvalo@...eaurora.org>;
> > Stanislaw Gruszka <sgruszka@...hat.com>; Benson Leung
> > <bleung@...omium.org>; Enric Balletbo i Serra
> > <enric.balletbo@...labora.com>; James E.J. Bottomley
> > <jejb@...ux.ibm.com>; Martin K. Petersen <martin.petersen@...cle.com>;
> > Greg Kroah-Hartman <gregkh@...uxfoundation.org>; Alexander Viro
> > <viro@...iv.linux.org.uk>; Sergey Senozhatsky
> > <sergey.senozhatsky@...il.com>; Steven Rostedt <rostedt@...dmis.org>;
> > Andrew Morton <akpm@...ux-foundation.org>; intel-
> > gfx@...ts.freedesktop.org; dri-devel@...ts.freedesktop.org; linux-
> > kernel@...r.kernel.org; netdev@...r.kernel.org;
> > ath10k@...ts.infradead.org; linux-wireless@...r.kernel.org; linux-
> > scsi@...r.kernel.org; linux-fbdev@...r.kernel.org;
> > devel@...verdev.osuosl.org; linux-fsdevel@...r.kernel.org
> > Subject: Re: [PATCH 1/4] lib/hexdump.c: Allow 64 bytes per line
> > 
> > On Wed 2019-04-10 13:17:17, Alastair D'Silva wrote:
> > > From: Alastair D'Silva <alastair@...ilva.org>
> > >
> > > With modern high resolution screens, we can display more data, which
> > > makes life a bit easier when debugging.
> > 
> > I have quite some doubts about this feature.
> > 
> > We are talking about more than 256 characters per-line. I wonder if such a
> > long line is really easier to read for a human.
> 
> It's basically 2 separate panes of information side by side, the hexdump and
> the ASCII version.
> 
> I'm using this myself when dealing with the pmem labels, and it works quite
> nicely.

I am sure that it works for you. But I do not believe that it
would be useful in general.


> > I am not expert but there is a reason why the standard is 80 characters
> per-
> > line. I guess that anything above 100 characters is questionable.
> > https://en.wikipedia.org/wiki/Line_length
> > somehow confirms that.
> > 
> > Second, if we take 8 pixels per-character. Then we need
> > 2048 to show the 256 characters. It is more than HD.
> > IMHO, there is still huge number of people that even do not have HD
> display,
> > especially on a notebook.
> 
> The intent is to make debugging easier when dealing with large chunks of
> binary data. I don't expect end users to see this output.

How is it supposed to be used then? Only by your temporary patches?

Best Regards,
Petr