From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2EAA5154C03; Tue, 22 Oct 2024 08:15:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729584922; cv=none; b=KiP5/7mwX5sWCLU4MT3R+eVVW3Dom4IYiG3EsYR7QZKMie6Z3unijmZ2HbH5tpG/JlHYKLuokODl9NSk33dEd1vRc0ol8BJk7PHxQQ/NaLegBt0A3vm5j9+Ha0NEKilp/onXdoFzs2uXcRyA5Uhqnhk1Z2Jy84DL42GWQiihl94= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729584922; c=relaxed/simple; bh=ED+LZhJhE26ThOoJvug3eIlGNitTZP5Mq2j85RJfjA0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=eRRP3RlGixPeXa1gCBxiNdj0qbKxfNOJlNPkf0dcjFqMIcFDRvmv9W5PPVTETFpPqCkqi0+e4uNaaiqKemjij5HXn81aE3Fur6nGVbapucu6oCBq+zpypAyo30Ea20CDHj3bQL7ibDp93kIL/deRMnvW0EBFASBMJ7fpLU8RiUg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ka8qOXVc; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Ka8qOXVc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 37DE2C4CEC3; Tue, 22 Oct 2024 08:15:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729584921; bh=ED+LZhJhE26ThOoJvug3eIlGNitTZP5Mq2j85RJfjA0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Ka8qOXVcbwuemlUXAnev4yBNY0NkM0WPW5XLI2Xv4xxSRjyH2PXtU1NX3OeQQ1DqR ctV44H/93iiU+iazoEDmIAcF5UZlUtyLumdw5/bvqk7vAAeb2umOphDF2hdmITv4ld 5Iq6FRxkQjSZIt1WfCG9ItMlVz6K7gqcLxGb4rgwoDr2ASCacNwpF3uanbgPb5c8pY dmIJzrGspNAFodoW1mSkKN/8r2EBNy0dgzSPREN8z22O5DGrXCZIL8ZzrHbShW5Vpq lwbDuU/CqHqZGvzLufVCMgNNZyoGCyFecBoChO1JyWdy2dvwbzlFK+QBWnObrV4fjq 6YfyORkX7yN9Q== Date: Tue, 22 Oct 2024 10:15:19 +0200 From: Maxime Ripard To: Liu Ying Cc: dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, andrzej.hajda@intel.com, neil.armstrong@linaro.org, rfoss@kernel.org, Laurent.pinchart@ideasonboard.com, jonas@kwiboo.se, jernej.skrabec@gmail.com, airlied@gmail.com, simona@ffwll.ch, maarten.lankhorst@linux.intel.com, tzimmermann@suse.de, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, quic_jesszhan@quicinc.com, mchehab@kernel.org, shawnguo@kernel.org, s.hauer@pengutronix.de, kernel@pengutronix.de, festevam@gmail.com, catalin.marinas@arm.com, will@kernel.org, sakari.ailus@linux.intel.com, hverkuil@xs4all.nl, tomi.valkeinen@ideasonboard.com, quic_bjorande@quicinc.com, geert+renesas@glider.be, dmitry.baryshkov@linaro.org, arnd@arndb.de, nfraprado@collabora.com, thierry.reding@gmail.com, prabhakar.mahadev-lad.rj@bp.renesas.com, sam@ravnborg.org, marex@denx.de, biju.das.jz@bp.renesas.com Subject: Re: [PATCH v3 12/15] drm/bridge: Add ITE IT6263 LVDS to HDMI converter Message-ID: <20241022-amazing-fresh-agouti-fb6eda@houat> References: <20241021064446.263619-1-victor.liu@nxp.com> <20241021064446.263619-13-victor.liu@nxp.com> <20241021-thick-cockle-of-popularity-c5e28c@houat> <889594b9-e6cb-4d90-b959-cd0258b2f166@nxp.com> <20241022-wondrous-fractal-lion-aedcd9@houat> <7a83230b-292c-4e28-813d-a07ea1b6a66a@nxp.com> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha384; protocol="application/pgp-signature"; boundary="u3pcdhq2tn2xfgvk" Content-Disposition: inline In-Reply-To: <7a83230b-292c-4e28-813d-a07ea1b6a66a@nxp.com> --u3pcdhq2tn2xfgvk Content-Type: text/plain; protected-headers=v1; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Subject: Re: [PATCH v3 12/15] drm/bridge: Add ITE IT6263 LVDS to HDMI converter MIME-Version: 1.0 On Tue, Oct 22, 2024 at 04:10:51PM +0800, Liu Ying wrote: > Hi Maxime, >=20 > On 10/22/2024, Maxime Ripard wrote: > > On Tue, Oct 22, 2024 at 03:36:47PM +0800, Liu Ying wrote: > >> Hi Maxime, > >> > >> On 10/21/2024, Maxime Ripard wrote: > >>> On Mon, Oct 21, 2024 at 02:44:43PM +0800, Liu Ying wrote: > >>>> +static int it6263_bridge_atomic_check(struct drm_bridge *bridge, > >>>> + struct drm_bridge_state *bridge_state, > >>>> + struct drm_crtc_state *crtc_state, > >>>> + struct drm_connector_state *conn_state) > >>>> +{ > >>>> + struct drm_display_mode *mode =3D &crtc_state->adjusted_mode; > >>>> + int ret; > >>>> + > >>>> + ret =3D drm_atomic_helper_connector_hdmi_check(conn_state->connect= or, > >>>> + conn_state->state); > >>>> + if (ret) > >>>> + return ret; > >>>> + > >>>> + return mode->clock > MAX_PIXEL_CLOCK_KHZ ? -EINVAL : 0; > >>> > >>> drm_atomic_helper_connector_hdmi_check will already make that check, = so > >>> it's redundant. > >> > >> MAX_PIXEL_CLOCK_KHZ is 150MHz. With 150MHz pixel clock rate, we'll get > >> 150MHz HDMI character rate for 8bpc and 187.5MHz HDMI character rate > >> for 10bpc, both are lower than MAX_HDMI_TMDS_CHAR_RATE_HZ =3D 225MHz. > >=20 > > I guess? I have no idea how that's relevant though. Where are those > > constraints coming from, and why aren't you checking for them in > > tmds_char_rate_valid? >=20 > All constraints come from IT6263 data sheet. They are also mentioned > in IT6263 product link(commit message contains the link). >=20 > https://www.ite.com.tw/en/product/cate1/IT6263 >=20 > " > LVDS RX > Support input clock rate up to 150 MHz >=20 > HDMI TX > Support link speeds of up to 2.25 Gbps (link clock rate of 225 MHz)=20 > " >=20 > If no objection, I'll check mode clock rate against > MAX_PIXEL_CLOCK_KHZ in tmds_char_rate_valid. If you don't support bpc other than 8, and no other format than RGB, then it's a good enough approximation. It should be documented though Maxime --u3pcdhq2tn2xfgvk Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iJUEABMJAB0WIQTkHFbLp4ejekA/qfgnX84Zoj2+dgUCZxdfFgAKCRAnX84Zoj2+ dkBpAYCTeWy3zA6iD+/mbISTuTA/oxVJr3H30Y/l4YAaYrxfiRnjSilMM+ckG3ph I3wUIxkBgO6JaDPbvX/C2fiSO1tM2GF/EadgjnJcVNSM3abhxJrUp3a2Z7LivwPC xgrGePQkkQ== =x6hs -----END PGP SIGNATURE----- --u3pcdhq2tn2xfgvk--