From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Smirl Subject: Re: fixing fbdev for various framebuffer configs Date: Fri, 29 Jul 2005 08:13:17 -0400 Message-ID: <9e47339105072905133da5fabc@mail.gmail.com> References: <9e473391050729035370d76cc5@mail.gmail.com> <42EA16A4.2050709@gmail.com> <9e47339105072904523afe0b9f@mail.gmail.com> Reply-To: linux-fbdev-devel@lists.sourceforge.net Mime-Version: 1.0 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.sourceforge.net with esmtp (Exim 4.30) id 1DyTjy-00031u-Bl for linux-fbdev-devel@lists.sourceforge.net; Fri, 29 Jul 2005 05:13:26 -0700 Received: from wproxy.gmail.com ([64.233.184.205]) by mail.sourceforge.net with esmtp (Exim 4.44) id 1DyTjv-000333-Tv for linux-fbdev-devel@lists.sourceforge.net; Fri, 29 Jul 2005 05:13:26 -0700 Received: by wproxy.gmail.com with SMTP id i3so622051wra for ; Fri, 29 Jul 2005 05:13:17 -0700 (PDT) In-Reply-To: Content-Disposition: inline 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="us-ascii" To: linux-fbdev-devel@lists.sourceforge.net Cc: "Antonino A. Daplas" , James Simmons On 7/29/05, Geert Uytterhoeven wrote: > On Fri, 29 Jul 2005, Jon Smirl wrote: > > On 7/29/05, Antonino A. Daplas wrote: > > > Jon Smirl wrote: > > > > It has been determined that bits per pixel is insuffucient to > > > > enumerate all the needed fbconfigs. Here are the possible fgconfigs > > > > from the OpenGL headers: > > > > > > > > total bits > > > > 8 GL_R3_G3_B2 > > > > 8 GL_RGBA2 > > > > 12 GL_RGB4 > > > > 15 GL_RGB5 > > > > 16 GL_R5_G6_B5 > > > > 16 GL_RGBA4 > > > > 16 GL_RGB5_A1 > > > > 24 GL_RGB8 > > > > 30 GL_RGB10 > > > > 32 GL_RGBA8 > > > > 32 GL_RGB10_A2 > > > > 36 GL_RGB12 > > > > 48 GL_RGB16 > > > > 48 GL_RGBA12 > > > > 48 GL_FLOAT_RGB16 > > > > 64 GL_RGBA16 > > > > 64 GL_FLOAT_RGBA16 > > > > 96 GL_FLOAT_RGB32 > > > > 128 GL_FLOAT_RGBA32 > > > > > > > > We need to be able to set any of these through the fbdev interface.= We > > > > also need to allow for possible future expansion. > > > > > > To set for example, RGBA16, set {transp|green|red|blue}.len to 16, th= e > > > offsets to 0, 16, 32, 48, and bits_per_pixel to 64. Then let the dri= ver > > > sort it out. I don't know what we can do about the FLOAT formats... > > > > > > > > > > > Ideas on how to adjust the fbdev interface? > > > > > > Well, no need to adjust the interface. But it is limited though to > > > 16 bits per channel. Redefining them to 32 will break a lot of apps. >=20 > It's only the colormap entries that are limited to 16 bits per color comp= onent, > right? The color components in pixel values can be much larger (up to 2^3= 1 bits > :-). >=20 > > My current idea is to get rid of the bit_per_pixel attribute and > > replace it with config. Config would take strings like 8,8,8 or > > 5,5,5,1 or 32.,32.,32. >=20 > That's not acceptable. How do you differentiate between RGB888 (without a= lpha) > using 24 or 32 bits per pixel? Isn't that the driver's problem? You can't differentiate using OpenGL. This does imply that I need a read only bits_per_pixel to allow apps to caculate the stride. > Or more general, what with hardware that has unused bits in its pixel val= ues, > e.g. hardware that has 8 bits per pixel but uses only 1 bit per byte in > monochrome mode and 4 bits in 16-color mode? >=20 > > > > What is the effect of alpha bits on the scanout buffer, do they do = anything? > > > > > > I think if there is another layer such as an overlay, the alpha bits = can > > > control the transparency between the framebuffer and the overlay. If = only > > > the framebuffer is active, I don't believe it has any effects. >=20 > It has on e.g. Set Top Box hardware. >=20 > Gr{oetje,eeting}s, >=20 > Geert >=20 > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m6= 8k.org >=20 > In personal conversations with technical people, I call myself a hacker. = But > when I'm talking to journalists I just say "programmer" or something like= that. > -- Linus Torv= alds >=20 >=20 > ------------------------------------------------------- > SF.Net email is Sponsored by the Better Software Conference & EXPO Septem= ber > 19-22, 2005 * San Francisco, CA * Development Lifecycle Practices > Agile & Plan-Driven Development * Managing Projects & Teams * Testing & Q= A > Security * Process Improvement & Measurement * http://www.sqe.com/bsce5sf > _______________________________________________ > Linux-fbdev-devel mailing list > Linux-fbdev-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linux-fbdev-devel >=20 --=20 Jon Smirl jonsmirl@gmail.com ------------------------------------------------------- SF.Net email is Sponsored by the Better Software Conference & EXPO September 19-22, 2005 * San Francisco, CA * Development Lifecycle Practices Agile & Plan-Driven Development * Managing Projects & Teams * Testing & QA Security * Process Improvement & Measurement * http://www.sqe.com/bsce5sf