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 70D8CCD343F for ; Fri, 15 May 2026 08:17:49 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id C190110E0E4; Fri, 15 May 2026 08:17:48 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="AH3Pu3Ej"; dkim-atps=neutral Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by gabe.freedesktop.org (Postfix) with ESMTPS id CAB8D10E0E4 for ; Fri, 15 May 2026 08:17:47 +0000 (UTC) Received: from [192.168.88.20] (91-158-153-178.elisa-laajakaista.fi [91.158.153.178]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 8908063C; Fri, 15 May 2026 10:17:35 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1778833056; bh=b0OEhP8qvyiis/NQ4grQI4aqjG0M9Ql0pGcC48E6k7k=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=AH3Pu3EjoCZzvtcnrUiKvK55iGeHCjQLkNPgq5qKvPw7mCpEdzLNiylbnbstODP0R Cf2zW43dk6zFuEO19RZJTSLTvsV/o4WBrBdKkVzGPM35zy2YzZrctfIhnqcyZQkFlX h7EN5XSWeuShMFS5p6wLUF1CD5AnDCJfTirm38x0= Message-ID: Date: Fri, 15 May 2026 11:17:42 +0300 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 3/5] drm/rcar-du: dsc: Add rudimentary Renesas R-Car V4H DSC driver To: Geert Uytterhoeven Cc: Michael Turquette , Stephen Boyd , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Magnus Damm , Marek Vasut , Laurent Pinchart , Kieran Bingham , Philipp Zabel , linux-renesas-soc@vger.kernel.org, linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org References: <20260514-rcar-du-dsc-v1-0-d65f7a9e9841@ideasonboard.com> <20260514-rcar-du-dsc-v1-3-d65f7a9e9841@ideasonboard.com> <6db159d9-56af-4d79-a1f1-9d5a6349b5ac@ideasonboard.com> From: Tomi Valkeinen Content-Language: en-US In-Reply-To: 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: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Hi, On 15/05/2026 11:05, Geert Uytterhoeven wrote: > Hi Tomi, > > On Fri, 15 May 2026 at 10:03, Tomi Valkeinen > wrote: >> On 15/05/2026 10:49, Geert Uytterhoeven wrote: >>> On Thu, 14 May 2026 at 14:25, Tomi Valkeinen >>> wrote: >>>> From: Marek Vasut >>>> >>>> The Renesas DSC Display Stream Compression is a bridge embedded in the >>>> Renesas R-Car V4H SoC. The bridge performs VESA DSC encoding of up to >>>> 8k or 400 Mpixel/s . Add rudimentary driver, which currently acts as a >>>> pass-through bridge and allows DSI1 to be operational on R-Car V4H. >>>> >>>> Signed-off-by: Marek Vasut >>>> [tomi.valkeinen: use bridge->next_bridge, minor changes] >>>> Signed-off-by: Tomi Valkeinen >>> >>> Thanks for your patch! >>> >>>> --- /dev/null >>>> +++ b/drivers/gpu/drm/renesas/rcar-du/rcar_dsc.c >>> >>>> + >>>> +static void rcar_dsc_atomic_enable(struct drm_bridge *bridge, >>>> + struct drm_atomic_state *state) >>>> +{ >>>> + struct rcar_dsc *dsc = bridge_to_rcar_dsc(bridge); >>>> + >>>> + WARN_ON(clk_prepare_enable(dsc->clk)); >> >> Ah, just missed your comment and sent the v2. >> >>> Who don't you use pm_runtime_resume_and_get() instead, like >>> rcar_cmm.c? Then you don't need to get the clock at all, and the driver >> >> Hmm, why wouldn't I need to get the clock? What does the runtime PM do >> on Renesas? > > Runtime PM powers on the power domain (if present), and starts > the device by enabling its module clock. > >>> will keep on working if the DSC ever ends up in a power domain. >> I can add runtime PM. I just felt that it was overcomplicating a "dummy" >> driver that just needs to enable the clock when the video pipeline is >> enabled. > > Funny, I would say you are overcomplicating a dummy driver by adding > explicit clock control ;-) Well, now that I know the runtime PM does magics behind the scenes, you are right =). How's "module clock" defined? Is it the first clock in the clocks DT property? I'll have a look at whitehawk too. The funny thing is, I had a recollection that dsc was somehow used on whitehawk too. I looked at the board, and saw only the single mini DP connector on the CPU board, which already works, so I then concluded that the other DSI path is for the GMSL... I think I need new eyeglasses. Tomi