From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262575AbVG2KeY (ORCPT ); Fri, 29 Jul 2005 06:34:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262563AbVG2KeY (ORCPT ); Fri, 29 Jul 2005 06:34:24 -0400 Received: from wproxy.gmail.com ([64.233.184.207]:29614 "EHLO wproxy.gmail.com") by vger.kernel.org with ESMTP id S262582AbVG2KeU convert rfc822-to-8bit (ORCPT ); Fri, 29 Jul 2005 06:34:20 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=Ud4rYkN2RwZujn4aBWQ0ek1fnkpkmuV17rPhucYNq5K6ainRZfA5rdyIzMzyjkRLakXWy4OyhGzM+R9itluz8PZ31xwS+Rp9vrvfcVzCyBF4WgjpB79zw4u36Wuwkn4Mq3ogCaetiwiH7FufHFdjcxYTZlG4ANXLdvtyBEmuqVA= Message-ID: <9e47339105072903345cb37164@mail.gmail.com> Date: Fri, 29 Jul 2005 06:34:20 -0400 From: Jon Smirl Reply-To: Jon Smirl To: linux-fbdev-devel@lists.sourceforge.net Subject: Re: [Linux-fbdev-devel] Re: [PATCH] fbdev: colormap fixes Cc: "Antonino A. Daplas" , Linux Kernel Development In-Reply-To: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Content-Disposition: inline References: <200507280031.j6S0V3L3016861@hera.kernel.org> <9e47339105072811183ac0f008@mail.gmail.com> <9e4733910507281315419c3c12@mail.gmail.com> <9e47339105072813213db7cee4@mail.gmail.com> <9e47339105072813507c00687e@mail.gmail.com> <9e47339105072814505b6fe4f8@mail.gmail.com> <42E95C05.7@pol.net> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On 7/29/05, Geert Uytterhoeven wrote: > On Fri, 29 Jul 2005, Antonino A. Daplas wrote: > > Jon Smirl wrote: > > > On 7/28/05, Geert Uytterhoeven wrote: > > > > On Thu, 28 Jul 2005, Jon Smirl wrote: > > > > > I've verified now that all ATI R300+ chips have 10bit cmaps. These are > > > > > pretty common so I'd be in favor of making this into a binary > > > > > attribute where I can get/set the whole table at once. Given that > > > > > OpenGL is already supporting 12 and 16 bits these tables are only > > > > > going to get much larger. > > > > > > > > > > 1024 entries * 5 fields * 2 bytes = 10KB -- too big for a text > > > > > attribute. > > > > > > > > > > 65536 entries * 5 fields * 2 bytes = 655KB -- way too big for a text > > > > > attribute. > > > > > > > > > > The bits_per_pixel sysfs attribute is an easy way to tell how many > > > > > entries you need. You can just set it at 4, 8, 10, etc until you get > > > > > an error. Now you know the max. 2^n and you know how many entries. > > > > No, bits_per_pixel can be (much) larger than the color map size. E.g. a > > > > simple > > > > ARGB8888 directcolor mode has bits_per_pixel = 32 and color map size = > > > > 256. > > > > > > So I have the bits_per_pixel attribute wrong in sysfs. It needs to be > > > bits_per_color and then let the driver sort it out. Otherwise there > > > is no way to set ARGB8888 versus ARGB2101010. With bits per color you > > > would set 8 or 10. > > > > No, you have to add another attribute for {transp|red|green|blue}.{len,offset} > > and another attribute for the pixelformat. Then using those, one can > > easily deduce the cmap size. > > Indeed. One bits_per_color cannot handle e.g. RGB565 (or RGBA{10,10,10,2} :-). > > > > If that isn't good enough I can switch the attribute to take strings > > > like ARGB8888. > > > > > > > Please no. > > Ack. > > > > What do you think, should I just switch to fbconfig names and a binary > > > cmap attribute? > > > > Does a binary attribute not have the same buffer size limitation as > > the text attribute? I really don't know, just asking. > > Yes it has, but since binary data is more compact, you can fit more data in > PAGE_SIZE. Binary attributes are not limited to page size. -- Jon Smirl jonsmirl@gmail.com