From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pigeon.gentoo.org ([208.92.234.80] helo=lists.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.77) (envelope-from ) id 1Sr9BV-0002VL-I2 for garchives@archives.gentoo.org; Tue, 17 Jul 2012 14:55:33 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 5037EE05E8; Tue, 17 Jul 2012 14:54:50 +0000 (UTC) Received: from mail-bk0-f53.google.com (mail-bk0-f53.google.com [209.85.214.53]) by pigeon.gentoo.org (Postfix) with ESMTP id 67441E06B1 for ; Tue, 17 Jul 2012 14:50:27 +0000 (UTC) Received: by bkwj4 with SMTP id j4so452426bkw.40 for ; Tue, 17 Jul 2012 07:50:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=Nx75M6rqevjkoIxZRVbjizG6gjuYuSKTDTCI1Zgbh/s=; b=UeZbcnJIoE9hu0LSpdLIzdU4vba1WRxl/TFGOGrnj27EVNzXcfczCv2wiztj+9E1pX /IPXziYcCzwlDB3FJ7YGflannrTMT60uFyoZnlB/7KSyli12Y3NfYA5H/R0klyZuLauC JBkXKNozr12Ft5DUPT7LXKC+2ilmRNyutd3cuq+456HA1GeeX6vX2ROQmmFFYgO3TLxz Q0N41VK4dknXDe/W5ajjA0QCZuiK6EV828KmZzcb1usWGzMlDYGNANejnQC7x9h1aJIo qZjTNRPqaJ3XnsIEW0S5IdDpxjUM5Yn1SN/urL1npc/3bg62GM7ghQeQeleKIAX3HdH3 mdtw== Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 Received: by 10.205.123.9 with SMTP id gi9mr1416975bkc.50.1342536626475; Tue, 17 Jul 2012 07:50:26 -0700 (PDT) Received: by 10.204.10.12 with HTTP; Tue, 17 Jul 2012 07:50:26 -0700 (PDT) In-Reply-To: References: <4F3ADE0C.9080204@gentoo.org> <44326664.PjbsZilTJI@core64> <50034A1B.3000506@gentoo.org> Date: Tue, 17 Jul 2012 10:50:26 -0400 Message-ID: Subject: Re: [gentoo-user] Running a USB graphics cards with Linux? From: Michael Mol To: gentoo-user@lists.gentoo.org Content-Type: text/plain; charset=UTF-8 X-Archives-Salt: 40889713-c2a6-4ec3-9274-8e4563a8a542 X-Archives-Hash: f1521fb5be8e7f1513c990f5cf23973e On Tue, Jul 17, 2012 at 10:03 AM, Kilian Zott wrote: > thats a strange comparison since usb is a serial bus > vga is not even digital, so how can you talk about throughput? lol Information doesn't need to be digital. Terms like 'bandwidth' really do apply. VGA does place some structure on its signal. You have a vertical and horizontal refresh rates. Your vertical refresh rate is usually in the 10s of Hz. I've seen displays range from 56Hz (terrible, terrible flicker on CRTs) to 120Hz (smooth as glass). Your horizontal refresh rates are usually in the 10s of *KHz*. The combination of the two dictated how many scanlines you could fit into your signal. Your number of pixels in a line was (in reality) limited by your video card's dot clock, but you might adjust things if you preferred, e.g. square pixels instead of whatever the per-pixel aspect ratio normally was. (I really don't rememeber.) Unlike DVI and HDMI, which support pixel formats that have subsampling, VGA didn't have any kind of compression mechanism. You had three channels, red, green and blue, and their voltage levels on the wire controlled the brightness of that color at whatever particular point on the display corresponded to that instant in your horizontal and vertical sweeps. If you'd like to know how I compare USB and VGA, look at ways VGA and DVI are analogous. Of course, under certain (now very unusual) circumstances, VGA can kick DVI's butt. -- :wq