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 A9048C433F5 for ; Tue, 8 Feb 2022 15:32:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1380487AbiBHPcV (ORCPT ); Tue, 8 Feb 2022 10:32:21 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45228 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1380449AbiBHPcQ (ORCPT ); Tue, 8 Feb 2022 10:32:16 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 57415C061579 for ; Tue, 8 Feb 2022 07:32:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1644334335; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=QnfSnxFE1VYyOfFPEeAqSReRud2yqkNu5yv4OL4UGFM=; b=UZasacGUzfKcR9GO7vKmB1t9I65RTH9UzymhHDSqpi/okSsOfUMBhgyvMjK92eZP4/D4Rq a9gNh6cN0kkKjFst69S9aU2Hp1/plIqCrpJ2JNV8CXTafj8491UVGDfBiyIChFnNw4+W+C QQ2Q0ZI0e9wmjcc/YyhR1+ayvx4YYHw= Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-128-i0BI_YH_NVuF_Oo9m20FpQ-1; Tue, 08 Feb 2022 10:32:14 -0500 X-MC-Unique: i0BI_YH_NVuF_Oo9m20FpQ-1 Received: by mail-wr1-f71.google.com with SMTP id q8-20020adfb188000000b001e33a8cdbf4so901243wra.16 for ; Tue, 08 Feb 2022 07:32:14 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=QnfSnxFE1VYyOfFPEeAqSReRud2yqkNu5yv4OL4UGFM=; b=FhI0K3BgcpQFMf8nRc3giDImZdDUoU34ezhKLtFahyvdsCwlspCP2Hh0lkeGVbdfxE JRne56RnhXFwkzriU4wobx2dy7Um61qCtga/YUfaHqcUp5I6WSKBNyVYlAbItXgc3wMY ancBOzSaOY7ygbZXtn/SAxVKwB9Stb7ev7yMpB81TfpTpKK4bl3ItGfI4RUo8XGJ+9IX pOIMKuHxZ+XJNaVasO0ZPDqnQYltFTJZl7dNL2ONTwA/QzA3pRJMl450l4/U+pbXRTcA vMSsftU3s4hwIk4lCucvx6PbTUKaxC1b8nvHDTM4cHqcbnuqU0QmGgYNibURS2DmIO0W bdDw== X-Gm-Message-State: AOAM531JbiT2fwJhmKoyUaybXcyOdpS0/XR6Eir5qYvXUy0VRodb9A2L S//zFZQoReSjjvvzxvweK8Qmq/0TvU5cGROjx6I5V4pKBA3oIsbxJtMl1NJy4wJPYve6zjo190j zSn3ryVyljmecKoX3WKf0QXGn X-Received: by 2002:a05:6000:178d:: with SMTP id e13mr4078660wrg.199.1644334333064; Tue, 08 Feb 2022 07:32:13 -0800 (PST) X-Google-Smtp-Source: ABdhPJx0uZ5F9GLuLEaXgNHD2jfvev/PazPYbXR3QUr3Uxy791l+CRAyYCO27d+KNpiT1o2GaLqxrQ== X-Received: by 2002:a05:6000:178d:: with SMTP id e13mr4078640wrg.199.1644334332831; Tue, 08 Feb 2022 07:32:12 -0800 (PST) Received: from [192.168.1.102] ([92.176.231.205]) by smtp.gmail.com with ESMTPSA id z17sm2451298wml.38.2022.02.08.07.32.11 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 08 Feb 2022 07:32:12 -0800 (PST) Message-ID: <10e06ad6-e8bd-a6de-3334-c682125e7753@redhat.com> Date: Tue, 8 Feb 2022 16:32:10 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH v2 0/4] drm/tiny: Add driver for Solomon SSD1307 OLED displays Content-Language: en-US To: Mark Brown Cc: "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Linux Fbdev development list , =?UTF-8?Q?Noralf_Tr=c3=b8nnes?= , Sam Ravnborg , Linux PWM List , David Airlie , Daniel Vetter , Linux Kernel Mailing List , DRI Development , Liam Girdwood , Rob Herring , Geert Uytterhoeven , Maxime Ripard , Thomas Zimmermann , =?UTF-8?Q?Uwe_Kleine-K=c3=b6nig?= , Thierry Reding , Andy Shevchenko , Lee Jones References: <20220204134347.1187749-1-javierm@redhat.com> From: Javier Martinez Canillas In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Mark, On 2/8/22 16:18, Mark Brown wrote: > On Tue, Feb 08, 2022 at 04:10:49PM +0100, Javier Martinez Canillas wrote: >> On 2/8/22 15:19, Geert Uytterhoeven wrote: > >>> - "time ls" on the serial console (no files in the current directory, >>> so nothing to print) increases from 0.86s to 1.92s, so the system is >>> more loaded. As ssd1307fb relied on deferred I/O too, the slowdown >>> might be (partly) due to redrawing of the visual artefacts >>> mentioned above. > >> I was trying to first have the driver and then figure out how to optimize >> it. For v3 I'm using regmap to access instead of the I2C layer directly. > >> I noticed that this is even slower but it makes the driver more clean and >> allows to support both I2C and SPI (untested but will include it as a WIP). > > I wouldn't have expected regmap to add huge overhead relative to I2C, > partly predicated on I2C being rather slow itself. There will be some > overhead for concurrency protection and data marshalling but for I2C > clocked at normal speeds it's surprising. Thanks for chiming in. That's good to know, I'll investigate more then. Probably I was wrongly blaming regmap while it was another change that is causing the display to be refreshed at a slower rate than before. Best regards, -- Javier Martinez Canillas Linux Engineering Red Hat