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[74.125.82.47]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-83f19f7cd19sm5196277b3a.54.2026.05.15.01.14.02 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 15 May 2026 01:14:02 -0700 (PDT) Received: by mail-dl1-f47.google.com with SMTP id a92af1059eb24-1329507c387so7342638c88.1 for ; Fri, 15 May 2026 01:14:02 -0700 (PDT) X-Forwarded-Encrypted: i=1; AFNElJ/BbHk2GOlmsWDIEzpCU6Lp6gxNFQARJYh2NyLb/oe+kFs+6NnOP/YmmFgX/nzej6YKvOCpqBTEzsk=@lists.freedesktop.org X-Received: by 2002:a05:6102:f94:b0:631:5ef5:8325 with SMTP id ada2fe7eead31-63a3d93b73cmr1247586137.8.1778832352115; Fri, 15 May 2026 01:05:52 -0700 (PDT) MIME-Version: 1.0 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> In-Reply-To: <6db159d9-56af-4d79-a1f1-9d5a6349b5ac@ideasonboard.com> From: Geert Uytterhoeven Date: Fri, 15 May 2026 10:05:41 +0200 X-Gmail-Original-Message-ID: X-Gm-Features: AVHnY4IeYtwx3NtqULFNQ1UNiQVfhuhx7vVBY8D7FKyQ3HU9Ed8VUzHO4jOvKfs Message-ID: Subject: Re: [PATCH 3/5] drm/rcar-du: dsc: Add rudimentary Renesas R-Car V4H DSC driver To: Tomi Valkeinen 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 Content-Type: text/plain; charset="UTF-8" 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 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 ;-) Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds