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 BB7C5C7EE2C for ; Tue, 30 May 2023 11:11:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229846AbjE3LL1 (ORCPT ); Tue, 30 May 2023 07:11:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54914 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231293AbjE3LLV (ORCPT ); Tue, 30 May 2023 07:11:21 -0400 Received: from mail-yw1-x112a.google.com (mail-yw1-x112a.google.com [IPv6:2607:f8b0:4864:20::112a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 346B8115 for ; Tue, 30 May 2023 04:11:19 -0700 (PDT) Received: by mail-yw1-x112a.google.com with SMTP id 00721157ae682-5664b14966bso29910337b3.1 for ; Tue, 30 May 2023 04:11:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1685445078; x=1688037078; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=2Aw1Y+LNx+6x6rqkl3hDGtyQpbkH+fbTyufgVbhUx3g=; b=j/znRIUxKJksQNwddxQU58ISTnn7vK+X/i5ctJxZ9kV6Zy74Y7/Ykn1i3yLD1unHfB g1n31aO8w98GIWhpkbzZdHOXZnpLE2VSfzmvc/YNKfYQ+LBduA0dV7wxL+4vq+e3GzxM sAdSD89FDbS9Y4yyVzNrAZCaHYJpp5Q4IIQoIbini+Vow6/Aj3cpWNe0+W6ligWOPT2u ARA3eKBN3lrXEJPxQhCOpk/6dZoqf4VOoqMec7n/yDYe8vrRCOvF8UzCReBELiA6OU9O T1cqBbP8F832jq3ASijrL+IzrUy3RQNNoH6YoT9idANpQ6ukYRvvIxPv5UNVQ9n5LYH9 Z0yA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1685445078; x=1688037078; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=2Aw1Y+LNx+6x6rqkl3hDGtyQpbkH+fbTyufgVbhUx3g=; b=NF6FKyCzMdVAUV31nBi6HG/JPGRCaga0f9ju2qVSP7PV6XjP8JlZxAflo8zlfCQSmZ 7PGYBVIjAnspO64dASJUzga8Rw7et8bAyqO1WxJq0TeR/NZLhCxGwYm0uBOdascIX8EV RD4hIQ4DAJwb0IVRWoM+dwpxFUmz1yifVkpPIkIimSib4eriZdWrOqLbp86vNK1cwRmv epelVkqh+JiwSAB4yq0nTg1amqymgH5ZXelve1KaFGzXr/wINTgmeLp02jIm6osCAMk1 u1KJeAapqxRCT9290KhwGoalKPONAK1QcJhTPi40/cJVg3+TlgCjHiabjxIa1JOs6DGA 3DIw== X-Gm-Message-State: AC+VfDws6eUOpayq6kFNjsyDLp5ed8QJ59MeRky6gG2wmcfatQTMb9RB GhV0/VNAWJuvQMZ8KOWrZuz/ze0UCNCX+b5zVJIiNw== X-Google-Smtp-Source: ACHHUZ5W8uyQC5KcaoA8JpMcpez1cJAmTKelhw60cKwxaP/qh9Nq55tKrVcBkj3EzUU6ZABnGEZGlGc1VHQoEZDvPAA= X-Received: by 2002:a0d:e212:0:b0:55d:a4fb:864a with SMTP id l18-20020a0de212000000b0055da4fb864amr1965071ywe.14.1685445078295; Tue, 30 May 2023 04:11:18 -0700 (PDT) MIME-Version: 1.0 References: <20230521-drm-panels-sony-v1-0-541c341d6bee@somainline.org> <20230521-drm-panels-sony-v1-3-541c341d6bee@somainline.org> <71675a02-0801-62dc-2673-4a0907636b21@linaro.org> In-Reply-To: From: Dmitry Baryshkov Date: Tue, 30 May 2023 14:11:06 +0300 Message-ID: Subject: Re: [PATCH RFC 03/10] drm/panel: Add LGD panel driver for Sony Xperia XZ3 To: Marijn Suijten Cc: neil.armstrong@linaro.org, Sam Ravnborg , David Airlie , Daniel Vetter , Caleb Connolly , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Andy Gross , Bjorn Andersson , ~postmarketos/upstreaming@lists.sr.ht, AngeloGioacchino Del Regno , Konrad Dybcio , Martin Botka , Jami Kettunen , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org, Abhinav Kumar , Kuogee Hsieh , Jessica Zhang Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 30 May 2023 at 11:27, Marijn Suijten wrote: > > On 2023-05-30 01:39:10, Dmitry Baryshkov wrote: > > On 30/05/2023 01:37, Marijn Suijten wrote: > > > On 2023-05-30 01:18:40, Dmitry Baryshkov wrote: > > > > > >>>>>>> + ret = mipi_dsi_dcs_set_display_on(dsi); > > >>>>>>> + if (ret < 0) { > > >>>>>>> + dev_err(dev, "Failed to turn display on: %d\n", ret); > > >>>>>>> + return ret; > > >>>>>>> + } > > >>>>>> > > >>>>>> My usual question: should the mipi_dsi_dcs_exit_sleep_mode() / mipi_dsi_dcs_set_display_on() be moved from prepare() to enable() part? > > >>>>> > > >>>>> > > >>>>> No, prepare is called before the video stream is started and when display is still in LPM mode and the mode hasn't been set. > > >>>>> > > >>>> > > >>>> Yes, that's my point. Shouldn't we enable the panel _after_ starting the stream? > > >>> > > >>> I have never investigated what it takes to split these functions, but > > >>> some of these panels do show some corruption at startup which may be > > >>> circumvented by powering the panel on after starting the video stream? > > >>> > > >>> I'm just not sure where to make the split: downstream does describe a > > >>> qcom,mdss-dsi-on-command and qcom,mdss-dsi-post-panel-on-command, where > > >>> the latter only contains set_display_on() (not exit_sleep_mode()). > > >>> It is documented like: > > >>> > > >>> same as "qcom,mdss-dsi-on-command" except commands are sent after > > >>> displaying an image." > > >>> > > >>> So this seems like the right way to split them up, I'll test this out on > > >>> all submitted panel drivers. > > >> > > >> Interesting enough, Neil suggested that sending all the commands during > > >> pre_enable() is the correct sequence (especially for VIDEO mode panels), > > >> since not all DSI hosts can send commands after switching to the VIDEO mode. > > > > > > Note that all these panels and Driver-ICs are command-mode, and/or > > > programmed to run in command-mode, so there shouldn't be any notion of a > > > VIDEO stream (any command-mode frame is just an "arbitrary command" as > > > far as I understood). > > > > Yes, from the data stream point of view. I was talking about the DSI > > host being able to send arbitrary commands or not after enabling the > > video/cmd stream. > > Is this a known limitation of SM8250 then? Or is the brightness_set > issue more likely a "problem" with the panel that the downstream kernel > is "somehow" working around or aware of, and I just haven't found > how/where it deals with that? > (Alternatively we could be "doing it wrong" for other panels but it > turns out to be working anyway) Please excuse me for not being explicit enough. Qualcomm hardware doesn't have this problem. Thus I was completely unaware of it before talking to Neil. So, our hardware works in most of the cases. -- With best wishes Dmitry