Re: FF layer restrictions [Was: [PATCH 1/1] Input: add sensable phantom driver]

From: "Dmitry Torokhov" <dmitry.torokhov@gmail.com>
To: "Jiri Slaby" <jirislaby@gmail.com>
Cc: "johann deneux" <johann.deneux@gmail.com>,
	"\"STenyaK (Bruno González)\"" <stenyak@gmail.com>,
	"Anssi Hannula" <anssi.hannula@gmail.com>,
	"Linux kernel mailing list" <linux-kernel@vger.kernel.org>,
	linux-input@atrey.karlin.mff.cuni.cz
Subject: Re: FF layer restrictions [Was: [PATCH 1/1] Input: add sensable phantom driver]
Date: Fri, 30 Mar 2007 12:46:41 -0400	[thread overview]
Message-ID: <d120d5000703300946k4268dfa0kadd3bf3094accd09@mail.gmail.com> (raw)
In-Reply-To: <460AEA8C.2050102@gmail.com>

On 3/28/07, Jiri Slaby <jirislaby@gmail.com> wrote:
> Jiri Slaby napsal(a):
> > Dmitry Torokhov napsal(a):
> >> On Tuesday 27 March 2007 17:34, johann deneux wrote:
> >>> What about adding a member to ff_effect which would be the number of the motor?
> >>> We can't change the layout of ff_effect too much though, so we have to
> >>> find unused bits and put them to work.
> >>>
> >>> For instance, we could replace
> >>>
> >>> __u16 type;
> >>>
> >>> by
> >>>
> >>> __u8 motor;
> >>> __u8 type;
> >>>
> >> Splitting type field seems to be a good idea.
> >
> > Maybe stupid question, but what about endianness + backward compatibility?
> > If we split it into motor,type sequence, it would break LE (untouched BE),
> > if we do type,motor, it is OK for LE (broken BE).
>
> Aha, and the question is: do
>
> #ifdef __BIG_ENDIAN
> #else
> #endif
>
> ?
>

I am so tempted to say "screw BE, there is not many users of FF layer"
but I am afraid we will have to do that #ifdef-fu.

-- 
Dmitry