From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ondrej Zajicek Subject: Re: Bug in vga16fb? Date: Thu, 6 Apr 2006 09:37:13 +0200 Message-ID: <20060406073713.GA3051@localhost.localdomain> References: <20060404204002.GB2251@localhost.localdomain> <44344950.9090703@vc.cvut.cz> Reply-To: linux-fbdev-devel@lists.sourceforge.net Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="rwEMma7ioTxnRzrJ" Return-path: Received: from sc8-sf-mx2-b.sourceforge.net ([10.3.1.92] helo=mail.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Exim 4.30) id 1FRP3S-0002fi-Ur for linux-fbdev-devel@lists.sourceforge.net; Thu, 06 Apr 2006 00:37:22 -0700 Received: from smtp1.kolej.mff.cuni.cz ([195.113.24.4]) by mail.sourceforge.net with esmtps (TLSv1:AES256-SHA:256) (Exim 4.44) id 1FRP3S-0005JU-Gc for linux-fbdev-devel@lists.sourceforge.net; Thu, 06 Apr 2006 00:37:23 -0700 Received: from localhost.localdomain (feanorr.kolej.mff.cuni.cz [195.113.26.209]) by smtp1.kolej.mff.cuni.cz (8.13.1/8.13.1) with ESMTP id k367bG1n043060 for ; Thu, 6 Apr 2006 09:37:17 +0200 (CEST) (envelope-from zajio1am@artax.karlin.mff.cuni.cz) Received: from santiago by localhost.localdomain with local (Exim 4.50) id 1FRP3J-0000p0-PF for linux-fbdev-devel@lists.sourceforge.net; Thu, 06 Apr 2006 09:37:13 +0200 Content-Disposition: inline In-Reply-To: <44344950.9090703@vc.cvut.cz> 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: To: linux-fbdev-devel@lists.sourceforge.net --rwEMma7ioTxnRzrJ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Apr 06, 2006 at 12:48:48AM +0200, Petr Vandrovec wrote: > Ondrej Zajicek wrote: > >Hello > > > >I tried vga16fb driver in 320x200x4 nonstd mode (on i386 - little endian= ).=20 > >In > >this mode framebuffer reports PACKED PIXELS type. Drawing through=20 > >framebuffer > >is OK, but console is broken - it looks like that even and odd columns a= re > >exchanged. > > > >Framebuffer structure of this mode is that even pixel is in high nibble = and > >odd pixel is in low nibble. > > > >It looks like vga16fb use cfbimgblt.c/slow_imageblit in this mode for > >image-blit and this function in CFB4 writes even pixel in low nibble and > >odd pixel in high nibble. > > > >What is correct framebuffer structure for CFB4 mode? >=20 > Unfortunately there is no standard, as CFB4 itself is quite non-standard= =20 > VGA mode. Some videocards first output low nibble, followed by high, and= =20 > some do otherwise. I've experimented with this back in 2000, and I've=20 > found that Matrox Millennium does exactly opposite than some ATI Mach64= =20 > card I had in another box at that time. >=20 > So your only option is providing two CFB4 modes. Unfortunately I have no= =20 > idea how to autodetect what your hardware actually does without adding=20 > camera to the system... Even if we find some possibility to autodetect what hardware does (or in case of another, non-VGA hardware using CFB4 mode) there would be problem that driver cannot say it to userspace (or generic kernel functions like cfb_imageblit). Maybe there should be some flag in type_aux specifying whether given packed pixel mode is LSB-first or MSB-first (relevant only for bpp % 8 !=3D 0) ? --=20 Elen sila lumenn' omentielvo Ondrej 'SanTiago' Zajicek (email: santiago@mail.cz, jabber: santiago@njs.ne= tlab.cz) OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net) "To err is human -- to blame it on a computer is even more so." --rwEMma7ioTxnRzrJ Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (GNU/Linux) iEYEARECAAYFAkQ0xSkACgkQw1GB2RHercMewgCfTL2KJIqIGx4Uqu7co4NjkXfp /C0An1uA0x0D7YHo6H8ZuU+Vkp6kuz6V =2ojV -----END PGP SIGNATURE----- --rwEMma7ioTxnRzrJ-- ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642