From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= Subject: Re: FB model basic issues (WAS: radeon, apertures & memory mapping) Date: Wed, 16 Mar 2005 01:05:22 +0200 Message-ID: <20050315230522.GA1444@sci.fi> References: <1110696189.5787.100.camel@gaston> <1110774523.4003.511.camel@localhost> <1110784327.5787.288.camel@gaston> <1110817205.4004.527.camel@localhost> <1110837171.5863.16.camel@gaston> <1110838356.4003.548.camel@localhost> <1110839873.5673.41.camel@gaston> <1110862777.4044.592.camel@localhost> <20050315060138.GA13064@sci.fi> <1110926659.25201.11.camel@gaston> Reply-To: linux-fbdev-devel@lists.sourceforge.net Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline In-Reply-To: <1110926659.25201.11.camel@gaston> Sender: linux-fbdev-devel-admin@lists.sourceforge.net Errors-To: linux-fbdev-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: List-Post: List-Help: List-Subscribe: , List-Archive: Content-Type: text/plain; charset="iso-8859-1" To: Benjamin Herrenschmidt Cc: Michel =?iso-8859-1?Q?D=E4nzer?= , dri-devel@lists.sourceforge.net, Linux Fbdev development list , xorg@lists.freedesktop.org, Jon Smirl On Wed, Mar 16, 2005 at 09:44:19AM +1100, Benjamin Herrenschmidt wrote: >=20 > > DirectFB assumes all memory outside var.yres_virtual * fix.line_lengt= h is=20 > > preserved. A totally valid assumption in my opinion.=20 >=20 > Except that you can't know in advance how much fix.line_length will be. > The "fix" isn't really "fixed". Different cards will have different > requirements depending on the bit depth for example. On radeonfb, the > line_length will vary due to alignment constraints related to the > engine, or due to tiling, etc.... etc... >=20 > So you basically don't know in advance what will be preserved... (And > you can't, unless you start having all sort of card specific knowledge)= . True. Currently DirectFB doesn't handle this correctly. But that could be= =20 easily fixed if only line_length wasn't totally misplaced. It really=20 belongs to fb_var_screeninfo. We could first test the mode with=20 FB_ACTIVATE_TEST and actually see how much memory it needs and could=20 evict enough offscreen surfaces to make room before actually setting the=20 mode. Currently it would need some guesswork. --=20 Ville Syrj=E4l=E4 syrjala@sci.fi http://www.sci.fi/~syrjala/ ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click