From owner-freebsd-arch@FreeBSD.ORG Mon Mar 3 00:11:12 2014 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 99DE0A6E; Mon, 3 Mar 2014 00:11:12 +0000 (UTC) Received: from mail-qa0-x229.google.com (mail-qa0-x229.google.com [IPv6:2607:f8b0:400d:c00::229]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 34533196B; Mon, 3 Mar 2014 00:11:12 +0000 (UTC) Received: by mail-qa0-f41.google.com with SMTP id j5so2874283qaq.28 for ; Sun, 02 Mar 2014 16:11:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=ia3dBPsKT8KMmv1rstIuXhm/u8wxoZOF0kSKvHkcYro=; b=cLmlqomivb3Gt2+rZM6VU+yLmvmHrGbsQG+1VpbdrLWJ25nU+MtoA9wr2eqVIX4BG6 Rtyod72g+tUn3pCOoBOg46LAGjXmFPnThk5lRZUZmh0Ul9tahJMPqnYOZwayGr91illy S4I6tfLu1AyQt5NtCvWIptAxAKcf8IDv+7ZJT7DGtjxRYiBeocDVdKqb+hFJhXZDoFlJ je8gQU8Hh6KnSoRsJNWwP7caJGsjzv3bjcCoTQ3oBYr7NzY7ViWy2E3qt6H4seaAhdlN nmbxuyp/cEtHQM9Ha7HiH2iBvWVZfqU5o4hiTUwA5icB6Ho+5VYwhjQL0E0z+lSiFXs0 XDSg== MIME-Version: 1.0 X-Received: by 10.224.136.67 with SMTP id q3mr15634266qat.8.1393805471350; Sun, 02 Mar 2014 16:11:11 -0800 (PST) Sender: adrian.chadd@gmail.com Received: by 10.224.16.10 with HTTP; Sun, 2 Mar 2014 16:11:11 -0800 (PST) In-Reply-To: <20140302085511.6354f9ac@zhabar.gateway.2wire.net> References: <20140302085511.6354f9ac@zhabar.gateway.2wire.net> Date: Sun, 2 Mar 2014 16:11:11 -0800 X-Google-Sender-Auth: glDqLmthvkkQcDmYsh-n9kFCd14 Message-ID: Subject: Re: newcons fb driver From: Adrian Chadd To: Justin Hibbits , Poul-Henning Kamp Content-Type: text/plain; charset=ISO-8859-1 Cc: "freebsd-arch@freebsd.org" X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 03 Mar 2014 00:11:12 -0000 .. i'm pretty sure there was a reason for why it's done in byte sizes. Maybe speak to phk? -a On 2 March 2014 08:55, wrote: > I've been looking into the slowness of the newcons framebuffer backend, > and after discussing with Nathan Whitehorn, we've determined that the > slowness is caused by single byte writes to the framebuffer, which are > very much suboptimal. His conclusion is that, on nVidia hardware, the > card first performs a read, a very slow operation on the hardware, then > a single-byte write, and I'm thinking the same. So, to accomodate this > limitation, I have a question and proposal: > > (q) From looking at the code, it appears to support, to some degree, a > background image (the character blitting uses a mask, it doesn't just > write background in that mask). Is this truly the case? > > (p) If it is the case that it supports a background image, I'm thinking > it would make sense to buffer the framebuffer, such that we write to > the internal representation, and blit whole words or lines at a time > to the hardware. With an 8-bit buffer, at 1920x1080 (common resolution) > we would be using approximately 2MB for the buffer. On memory > constrained devices this can be quite significant, so it becomes a > tradeoff. > > Thoughts? > > - Justin > _______________________________________________ > freebsd-arch@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-arch > To unsubscribe, send any mail to "freebsd-arch-unsubscribe@freebsd.org"