From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= Subject: Re: [PATCH] Do set var even if no fb_check_var() provided. Date: Thu, 28 Aug 2008 10:45:21 +0300 Message-ID: <20080828074521.GO16680@sci.fi> References: <48B4E16C.4000107@renesas.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.91] helo=mail.sourceforge.net) by sc8-sf-list1-new.sourceforge.net with esmtp (Exim 4.43) id 1KYcCA-000102-6K for linux-fbdev-devel@lists.sourceforge.net; Thu, 28 Aug 2008 00:45:30 -0700 Received: from smtp4.pp.htv.fi ([213.243.153.38]) by mail.sourceforge.net with esmtp (Exim 4.44) id 1KYcC7-0004iJ-I4 for linux-fbdev-devel@lists.sourceforge.net; Thu, 28 Aug 2008 00:45:30 -0700 Content-Disposition: inline In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-fbdev-devel-bounces@lists.sourceforge.net Errors-To: linux-fbdev-devel-bounces@lists.sourceforge.net To: Helge Deller Cc: linux-fbdev-devel@lists.sourceforge.net On Wed, Aug 27, 2008 at 11:49:15PM +0200, Helge Deller wrote: > Geert Uytterhoeven wrote: > > On Wed, 27 Aug 2008, Takashi Yoshii wrote: > >> The behavior of FBIOSET_VSCREENINFO seems to be weired on FB which does > >> not > >> provides fbops->fb_check_var. > >> It doesn't set anything, but gets info->var instead, and returns no > >> error. It is just same as FBIOGET_VSCREENINFO does. > >> = > >> IMHO, this should be one of the following candidates, > >> 1. set var without check. > >> 2. do nothing but return error (setting var is not supported). > >> or > >> 3. it's a bug (fb_check_var should always be provided). > >> = > >> The patch at the bottom implements "1". > >> = > >> Because I don't know API specification, nor the history of the code, > >> I would like people who knows well to discuss this. > > = > > If the driver doesn't provide a fb_check_var(), it means it cannot > > change video mode. Hence this rules out #1. > > = > > #2 is not acceptable, as it will break existing applications. It's also > > incorrect, as FBIOPUT_VSCREENINFO should succeed for supported modes. > > For unsupported modes, the mode should be rounded up to a supported mod= e, > > if possible. In the case of drivers that support one fixed mode only, t= his > > rounding up is relaxed to `rounding' to the sole supported mode. > > = > > #3 is also wrong, as fb_check_var() has been deliberately made optional= to > > simplify drivers that support one fixed mode only. > > = > > Conclusion: nothing should be changed? > = > I'm not sure. > On parisc we just stumbled over exactly this problem where I think Takash= i's > proposal "1." is probably the right solution. What about this? 4. Provide a generic check_var() that does some basic sanity checking against info->var (eg. check xres, yres and bits_per_pixel). -- = Ville Syrj=E4l=E4 syrjala@sci.fi http://www.sci.fi/~syrjala/ ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great priz= es Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=3D100&url=3D/