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dmarc=none (p=none dis=none) header.from=bootlin.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender:Content-Type:Cc: List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: In-Reply-To:MIME-Version:References:Message-ID:Subject:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=YnsYRqmKTlVX2DW2gzKiqDNoLNQoDzvK74hLYaI1frA=; b=aExX9PfPiw6SR+cRhugK4AYhD IVThC/MZDqIq9pTfsZ0FEb7mHxaolpna1Z7M8CcuoHspKnOVyHIquKL4F5MHZ6Emg/rvP4Ak4nDWe 27QE/6Xf4VQtAmQ5r4LLTuo/NgkDAZeUf7wYeA5sKawNCcXWk9KRzw+pF4A5Z/K2h4jaYuq65FUhX nV2HnCQvd2fgdwAG+23XoHB4WbsPFxonmdy8Wequ+s7xRXM/yc1V8oaWYHIIp8knKEzO58biaTWG/ a5ZlE72dUZ1/clufRcJDChEMOJXkVViQbtfd3nDhZtm2yuTxyMnYhWQ2XsKKoSl4tHRDbuNiNaeXg AtsJY/qgg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gqf7B-0000Ah-9E; Mon, 04 Feb 2019 14:20:49 +0000 Received: from relay6-d.mail.gandi.net ([217.70.183.198]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gqf77-0000A3-Aw for linux-arm-kernel@lists.infradead.org; Mon, 04 Feb 2019 14:20:47 +0000 X-Originating-IP: 185.94.189.188 Received: from localhost (unknown [185.94.189.188]) (Authenticated sender: maxime.ripard@bootlin.com) by relay6-d.mail.gandi.net (Postfix) with ESMTPSA id A4528C0018; Mon, 4 Feb 2019 14:20:36 +0000 (UTC) Date: Mon, 4 Feb 2019 15:20:36 +0100 From: Maxime Ripard To: Vasily Khoruzhick Subject: Re: [PATCH RESEND v2 06/12] drm/sun4i: rgb: Add 1% tolerance to dclk frequency check when bridge is connected Message-ID: <20190204142036.vd42nvyjnjr5yeoi@flea> References: <20190203185501.8958-1-anarsoul@gmail.com> <20190203185501.8958-7-anarsoul@gmail.com> MIME-Version: 1.0 In-Reply-To: <20190203185501.8958-7-anarsoul@gmail.com> User-Agent: NeoMutt/20180716 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190204_062045_530468_E93A428C X-CRM114-Status: GOOD ( 14.37 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , devicetree@vger.kernel.org, Archit Taneja , David Airlie , linux-sunxi@googlegroups.com, dri-devel@lists.freedesktop.org, Andrzej Hajda , Chen-Yu Tsai , Rob Herring , Thierry Reding , Laurent Pinchart , Daniel Vetter , Sean Paul , linux-arm-kernel@lists.infradead.org, Icenowy Zheng Content-Type: multipart/mixed; boundary="===============2685625986583520057==" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org --===============2685625986583520057== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="pki7yqddvb65jqxg" Content-Disposition: inline --pki7yqddvb65jqxg Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi, On Sun, Feb 03, 2019 at 10:54:55AM -0800, Vasily Khoruzhick wrote: > Clock rate check that was added in commit bb43d40d7c83 ("drm/sun4i: rgb: > Validate the clock rate") prevents some panel and bridges from working wi= th > sun4i driver. >=20 > Unfortunately, dotclock frequency for some modes are not achievable on > sunxi hardware, and there's a slight deviation in rate returned by > clk_round_rate(), so they fail this check. >=20 > Experiments show that panels and bridges work fine with this slight > deviation, e.g. Pinebook that uses ANX6345 bridge with 768p eDP panel > requests 73 MHz, gets 72.296MHz instead (0.96% difference) and works just > fine. >=20 > This patch adds a 1% tolerence to the dot clock check when bridge is > connected. >=20 > Signed-off-by: Vasily Khoruzhick I'm not sure we want to make exceptions for all the hardware combination we face, but we should go for something more generic (and easier to maintain instead). IIRC, from the previous discussion, HDMI had a tolerancy requirement in the standard. Do you know if there's such a thing for eDP? That would solve the issue for all the eDP displays at once. Maxime --=20 Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com --pki7yqddvb65jqxg Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRcEzekXsqa64kGDp7j7w1vZxhRxQUCXFhKNAAKCRDj7w1vZxhR xWUOAP9CVAT9LZonfV+XcI1sWCKpFeNqOib3yRnZjpYCqcmi3AEAtNUoPnU23f4B xN2AALu0GLWrxwE4xuMHC5WbxDWLmAc= =yHkr -----END PGP SIGNATURE----- --pki7yqddvb65jqxg-- --===============2685625986583520057== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel --===============2685625986583520057==--