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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id ECBC3C433F5 for ; Tue, 12 Apr 2022 14:25:05 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 1A95510E28D; Tue, 12 Apr 2022 14:25:05 +0000 (UTC) Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by gabe.freedesktop.org (Postfix) with ESMTPS id 2C0FA10E28D for ; Tue, 12 Apr 2022 14:25:04 +0000 (UTC) Received: from [192.168.1.111] (91-156-85-209.elisa-laajakaista.fi [91.156.85.209]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 53F24486; Tue, 12 Apr 2022 16:25:01 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1649773502; bh=TD/bZV0n+8gOuaITuXISCNvKDTaVocldAK+mP8GfBLA=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=qWqtmbG+qDmmBC5ucGcMjlZotm5YfmGMe11bdqgwIAxkUhErnX5V1SOMFJ22CqFaN oybAlLuQC0/8TaltkrMd7+POolRP0MdihrnqljtTSoChK5/8v4nh6n4qKVu5R17Stq AwZSOW0KWK4kgTn0lwILUtQF6vdaIuB45sV8TBPI= Message-ID: <86a07099-1074-e8d1-6d0e-1ce68414b627@ideasonboard.com> Date: Tue, 12 Apr 2022 17:24:58 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [PATCH] drm/tidss: Soft Reset DISPC on startup Content-Language: en-US To: Devarsh Thakkar , linux-kernel@vger.kernel.org, jyri.sarha@iki.fi, tomba@kernel.org, airlied@linux.ie, daniel@ffwll.ch, dri-devel@lists.freedesktop.org References: <20220314113739.18000-1-devarsht@ti.com> From: Tomi Valkeinen In-Reply-To: <20220314113739.18000-1-devarsht@ti.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: nm@ti.com, vigneshr@ti.com, a-bhatia1@ti.com, laurent.pinchart@ideasonboard.com, nikhil.nd@ti.com, linux-arm-kernel@lists.infradead.org, r-ravikumar@ti.com Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Hi, On 14/03/2022 13:37, Devarsh Thakkar wrote: > Soft reset the display subsystem controller on startup and wait for > the reset to complete. This helps the scenario where display was > already in use by some other core before the linux was booted. The reason the omapdrm doesn't do a reset is that the PM features on some of the DSS registers were set and controlled outside dss driver, so the dss driver could not do a reset just like that. That design was carried to the tidss driver, although I'm not sure if the reason is valid on AM6 and J7 platforms. If that reasoning is not valid, this patch is ok and: Reviewed-by: Tomi Valkeinen Tomi > Signed-off-by: Devarsh Thakkar > --- > drivers/gpu/drm/tidss/tidss_dispc.c | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/drivers/gpu/drm/tidss/tidss_dispc.c b/drivers/gpu/drm/tidss/tidss_dispc.c > index 60b92df615aa..dae47853b728 100644 > --- a/drivers/gpu/drm/tidss/tidss_dispc.c > +++ b/drivers/gpu/drm/tidss/tidss_dispc.c > @@ -2650,6 +2650,20 @@ static void dispc_init_errata(struct dispc_device *dispc) > } > } > > +static void dispc_softreset(struct dispc_device *dispc) > +{ > + u32 val; > + int ret = 0; > + > + /* Soft reset */ > + REG_FLD_MOD(dispc, DSS_SYSCONFIG, 1, 1, 1); > + /* Wait for reset to complete */ > + ret = readl_poll_timeout(dispc->base_common + DSS_SYSSTATUS, > + val, val & 1, 100, 5000); > + if (ret) > + dev_warn(dispc->dev, "failed to reset dispc\n"); > +} > + > int dispc_init(struct tidss_device *tidss) > { > struct device *dev = tidss->dev; > @@ -2709,6 +2723,10 @@ int dispc_init(struct tidss_device *tidss) > return r; > } > > + /* K2G display controller does not support soft reset */ > + if (feat->subrev != DISPC_K2G) > + dispc_softreset(dispc); > + > for (i = 0; i < dispc->feat->num_vps; i++) { > u32 gamma_size = dispc->feat->vp_feat.color.gamma_size; > u32 *gamma_table;