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 2B665C001DE for ; Tue, 25 Jul 2023 16:42:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230126AbjGYQm5 (ORCPT ); Tue, 25 Jul 2023 12:42:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37658 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229499AbjGYQm4 (ORCPT ); Tue, 25 Jul 2023 12:42:56 -0400 Received: from 1wt.eu (ded1.1wt.eu [163.172.96.212]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id A479DE4 for ; Tue, 25 Jul 2023 09:42:54 -0700 (PDT) Received: (from willy@localhost) by mail.home.local (8.17.1/8.17.1/Submit) id 36PGgdrn007324; Tue, 25 Jul 2023 18:42:39 +0200 Date: Tue, 25 Jul 2023 18:42:39 +0200 From: Willy Tarreau To: Geert Uytterhoeven Cc: Hugo Villeneuve , Miguel Ojeda , Hugo Villeneuve , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] auxdisplay: hd44780: move cursor home after clear display command Message-ID: References: <20230722180925.1408885-1-hugo@hugovil.com> <20230725111354.160f32cfba0b53923ac2aae6@hugovil.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 25, 2023 at 05:58:45PM +0200, Geert Uytterhoeven wrote: > > One thing I'm having in mind is that this LCD supported horizontal > > scrolling to show the off-screen columns. I'm wondering if the gotoxy() > > and home() did the same thing regarding this. Maybe gotoxy() scrolled > > back to 0,0 while home() just moved the cursor to the visible home > > without scrolling back, in which case it could make a difference. > > Indeed, at least according to the real HD44780 documentation, > Return Home also resets the scrolling. OK, thanks for checking! > > I would suggest that we just stick to the specs and see if anyone reports > > any trouble. There are so many compatible devices nowadays that possibly > > implement only a subset of the original controller that we should really > > stick to what is clearly understood by everyone and not rely on some old > > conclusions about vague observations made by me 25 years ago! > > OK. Given this patch is also a workaround for an incomplete > implementation, let's keep hd44780_common_home() as-is. OK, works for me. Thanks, Willy