From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B17AFC433EF for ; Thu, 24 Feb 2022 10:30:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232725AbiBXKad (ORCPT ); Thu, 24 Feb 2022 05:30:33 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50128 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231235AbiBXKac (ORCPT ); Thu, 24 Feb 2022 05:30:32 -0500 Received: from mx2.smtp.larsendata.com (mx2.smtp.larsendata.com [91.221.196.228]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 06FB728F45D for ; Thu, 24 Feb 2022 02:30:00 -0800 (PST) Received: from mail01.mxhotel.dk (mail01.mxhotel.dk [91.221.196.236]) by mx2.smtp.larsendata.com (Halon) with ESMTPS id c30dee63-955c-11ec-b2df-0050568cd888; Thu, 24 Feb 2022 10:30:18 +0000 (UTC) Received: from ravnborg.org (80-162-45-141-cable.dk.customer.tdc.net [80.162.45.141]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: sam@ravnborg.org) by mail01.mxhotel.dk (Postfix) with ESMTPSA id 48650194B49; Thu, 24 Feb 2022 11:30:02 +0100 (CET) Date: Thu, 24 Feb 2022 11:29:55 +0100 X-Report-Abuse-To: abuse@mxhotel.dk From: Sam Ravnborg To: Javier Martinez Canillas Cc: Thomas Zimmermann , daniel@ffwll.ch, deller@gmx.de, geert@linux-m68k.org, kraxel@redhat.com, ppaalanen@gmail.com, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org Subject: Re: [PATCH v3 4/5] fbdev: Improve performance of cfb_imageblit() Message-ID: References: <20220223193804.18636-1-tzimmermann@suse.de> <20220223193804.18636-5-tzimmermann@suse.de> <02cd3c81-d937-eb2a-ebe1-3eb9d83f6adc@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <02cd3c81-d937-eb2a-ebe1-3eb9d83f6adc@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org Hi Javier, On Thu, Feb 24, 2022 at 10:02:59AM +0100, Javier Martinez Canillas wrote: > Hello Sam, > > On 2/23/22 21:25, Sam Ravnborg wrote: > > [snip] > > > > > Question: What is cfb an abbreviation for anyway? > > Not related to the patch - but if I have known the memory is lost.. > > > > I was curious so I dug on this. It seems CFB stands for Color Frame Buffer. > Doing a `git grep "(CFB)"` in the linux history repo [0], I get this: > > Documentation/isdn/README.diversion: (CFB). > drivers/video/pmag-ba-fb.c: * PMAG-BA TURBOchannel Color Frame Buffer (CFB) card support, > include/video/pmag-ba-fb.h: * TURBOchannel PMAG-BA Color Frame Buffer (CFB) card support, > > Probably the helpers are called like this because they were for any fbdev > driver but assumed that the framebuffer was always in I/O memory. Later some > drivers were allocating the framebuffer in system memory and still using the > helpers, that were using I/O memory accessors and it's ilegal on some arches. > > So the sys_* variants where introduced by commit 68648ed1f58d ("fbdev: add > drawing functions for framebuffers in system RAM") to fix this. The old > ones just kept their name, but probably it should had been renamed to io_* > for the naming to be consistent with the sys_* functions. > > [0]: https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/ Interesting - thanks for the history lesson and thanks for taking your time to share your findings too. Sam