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 X-Spam-Level: X-Spam-Status: No, score=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33F4BC5B576 for ; Sun, 30 Jun 2019 20:47:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 024D1217D8 for ; Sun, 30 Jun 2019 20:47:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="JvQhk0CY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726830AbfF3Urq (ORCPT ); Sun, 30 Jun 2019 16:47:46 -0400 Received: from perceval.ideasonboard.com ([213.167.242.64]:48718 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726669AbfF3Urq (ORCPT ); Sun, 30 Jun 2019 16:47:46 -0400 Received: from pendragon.ideasonboard.com (dfj612yhrgyx302h3jwwy-3.rev.dnainternet.fi [IPv6:2001:14ba:21f5:5b00:ce28:277f:58d7:3ca4]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 47CFD255; Sun, 30 Jun 2019 22:47:43 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1561927663; bh=dBe3yAq6Q1C4VcXG06Vz7nXaIG0pbndeYddXgCeKg/A=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=JvQhk0CYuLPmvsnXgMfQ54qleQCRDC8h/euYya5WJKEGZT4y8cPE6Qkd/pT7ktb2c BNXwwxE1Vl5Rh76y5JDDSQFISCh4/fpR2a+4HdNPKJdBK14JEHP2ycWds3maKAy/UD Ef8mWClZdv+sgFXvRnCu62dq9xZKjV4vxoaEy31k= Date: Sun, 30 Jun 2019 23:47:23 +0300 From: Laurent Pinchart To: Rob Clark Cc: dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org, aarch64-laptops@lists.linaro.org, Rob Clark , Ard Biesheuvel , Catalin Marinas , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Ingo Molnar , Julien Thierry , "open list:EXTENSIBLE FIRMWARE INTERFACE (EFI)" , open list , Lukas Wunner , Steve Capper , Will Deacon Subject: Re: [PATCH 0/4] drm+dt+efi: support devices with multiple possible panels Message-ID: <20190630204723.GH7043@pendragon.ideasonboard.com> References: <20190630203614.5290-1-robdclark@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190630203614.5290-1-robdclark@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org Hi Rob, Thank you for the patch. On Sun, Jun 30, 2019 at 01:36:04PM -0700, Rob Clark wrote: > From: Rob Clark > > Now that we can deal gracefully with bootloader (firmware) initialized > display on aarch64 laptops[1], the next step is to deal with the fact > that the same model of laptop can have one of multiple different panels. > (For the yoga c630 that I have, I know of at least two possible panels, > there might be a third.) I have to ask the obvious question: why doesn't the boot loader just pass a correct DT to Linux ? There's no point in passing a list of panels that are not there, this seems quite a big hack to me. A proper boot loader should construct the DT based on hardware detection. > This is actually a scenario that comes up frequently in phones and > tablets as well, so it is useful to have an upstream solution for this. > > The basic idea is to add a 'panel-id' property in dt chosen node, and > use that to pick the endpoint we look at when loading the panel driver, > e.g. > > / { > chosen { > panel-id = <0xc4>; > }; > > ivo_panel { > compatible = "ivo,m133nwf4-r0"; > power-supply = <&vlcm_3v3>; > no-hpd; > > ports { > port { > ivo_panel_in_edp: endpoint { > remote-endpoint = <&sn65dsi86_out_ivo>; > }; > }; > }; > }; > > boe_panel { > compatible = "boe,nv133fhm-n61"; > power-supply = <&vlcm_3v3>; > no-hpd; > > ports { > port { > boe_panel_in_edp: endpoint { > remote-endpoint = <&sn65dsi86_out_boe>; > }; > }; > }; > }; > > sn65dsi86: bridge@2c { > compatible = "ti,sn65dsi86"; > > ... > > ports { > #address-cells = <1>; > #size-cells = <0>; > > ... > > port@1 { > #address-cells = <1>; > #size-cells = <0>; > reg = <1>; > > endpoint@c4 { > reg = <0xc4>; > remote-endpoint = <&boe_panel_in_edp>; > }; > > endpoint@c5 { > reg = <0xc5>; > remote-endpoint = <&ivo_panel_in_edp>; > }; > }; > }; > } > }; > > Note that the panel-id is potentially a sparse-int. The values I've > seen so far on aarch64 laptops are: > > * 0xc2 > * 0xc3 > * 0xc4 > * 0xc5 > * 0x8011 > * 0x8012 > * 0x8055 > * 0x8056 > > At least on snapdragon aarch64 laptops, they can be any u32 value. > > However, on these laptops, the bootloader/firmware is not populating the > chosen node, but instead providing an "UEFIDisplayInfo" variable, which > contains the panel id. Unfortunately EFI variables are only available > before ExitBootServices, so the second patch checks for this variable > before EBS and populates the /chosen/panel-id variable. > > [1] https://patchwork.freedesktop.org/series/63001/ > > Rob Clark (4): > dt-bindings: chosen: document panel-id binding > efi/libstub: detect panel-id > drm: add helper to lookup panel-id > drm/bridge: ti-sn65dsi86: use helper to lookup panel-id > > Documentation/devicetree/bindings/chosen.txt | 69 ++++++++++++++++++++ > drivers/firmware/efi/libstub/arm-stub.c | 49 ++++++++++++++ > drivers/firmware/efi/libstub/efistub.h | 2 + > drivers/firmware/efi/libstub/fdt.c | 9 +++ > drivers/gpu/drm/bridge/ti-sn65dsi86.c | 5 +- > drivers/gpu/drm/drm_of.c | 21 ++++++ > include/drm/drm_of.h | 7 ++ > 7 files changed, 160 insertions(+), 2 deletions(-) -- Regards, Laurent Pinchart