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Date:   Mon, 1 Feb 2021 10:23:17 +0100
From:   Michael Tretter <m.tretter@pengutronix.de>
To:     David Laight <David.Laight@ACULAB.COM>
Cc:     'Emmanuel Arias' <eamanu@yaerobi.com>,
        "kernel@pengutronix.de" <kernel@pengutronix.de>,
        "mchehab@kernel.org" <mchehab@kernel.org>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
        "linux-media@vger.kernel.org" <linux-media@vger.kernel.org>,
        "devel@driverdev.osuosl.org" <devel@driverdev.osuosl.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] media: allegro-dvt: Use __packed sentence
Message-ID: <20210201092317.GB6717@pengutronix.de>
Mail-Followup-To: Michael Tretter <m.tretter@pengutronix.de>,
        David Laight <David.Laight@ACULAB.COM>,
        'Emmanuel Arias' <eamanu@yaerobi.com>,
        "kernel@pengutronix.de" <kernel@pengutronix.de>,
        "mchehab@kernel.org" <mchehab@kernel.org>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
        "linux-media@vger.kernel.org" <linux-media@vger.kernel.org>,
        "devel@driverdev.osuosl.org" <devel@driverdev.osuosl.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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On Fri, 29 Jan 2021 23:54:41 +0000, David Laight wrote:
> From: Emmanuel Arias
> > Sent: 29 January 2021 20:02
> > 
> > Fix coding style using __packed sentece instead of
> > __attribute__((__packed__)).
> > 
> > Signed-off-by: Emmanuel Arias <eamanu@yaerobi.com>
> > ---
> >  drivers/staging/media/allegro-dvt/allegro-core.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/staging/media/allegro-dvt/allegro-core.c b/drivers/staging/media/allegro-
> > dvt/allegro-core.c
> > index 9f718f43282b..cee624dac61a 100644
> > --- a/drivers/staging/media/allegro-dvt/allegro-core.c
> > +++ b/drivers/staging/media/allegro-dvt/allegro-core.c
> > @@ -670,7 +670,7 @@ static ssize_t allegro_mbox_read(struct allegro_mbox *mbox,
> >  	struct {
> >  		u16 length;
> >  		u16 type;
> > -	} __attribute__ ((__packed__)) *header;
> > +	} __packed *header;
> >  	struct regmap *sram = mbox->dev->sram;
> 
> Does this actually need to be packed?
> The only reason would be if the structure could exist on a 2n+1
> boundary.

Not sure, what you mean by this.

> But that is only likely if part of some binary sequence.
> In which case I'd expect it to be marked __be or __le.

It is part of a binary sequence. It is the header of messages in a mailbox
that is used to exchange data with a co-processor (video encoder). In fact, it
should be marked as __le.

Michael