From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753877AbcI1Lzl (ORCPT ); Wed, 28 Sep 2016 07:55:41 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:60856 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753599AbcI1Lz1 (ORCPT ); Wed, 28 Sep 2016 07:55:27 -0400 Subject: Re: [PATCH] drm: tilcdc: add a workaround for failed clk_set_rate() To: Bartosz Golaszewski References: <1474990196-808-1-git-send-email-bgolaszewski@baylibre.com> <8136a79b-23b8-d353-8602-428cc20947f6@ti.com> CC: Jyri Sarha , David Airlie , Kevin Hilman , Michael Turquette , linux-drm , LKML , Sekhar Nori From: Tomi Valkeinen Message-ID: <39ca356b-6cf5-e905-1d22-284014b7318e@ti.com> Date: Wed, 28 Sep 2016 14:55:18 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="KcPPfFrdWmNEaufki21lhrWb1weRa5N71" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --KcPPfFrdWmNEaufki21lhrWb1weRa5N71 Content-Type: multipart/mixed; boundary="jLT0SV5vR1EVCnLLHqxnUb63HqI84MwAa"; protected-headers="v1" From: Tomi Valkeinen To: Bartosz Golaszewski Cc: Jyri Sarha , David Airlie , Kevin Hilman , Michael Turquette , linux-drm , LKML , Sekhar Nori Message-ID: <39ca356b-6cf5-e905-1d22-284014b7318e@ti.com> Subject: Re: [PATCH] drm: tilcdc: add a workaround for failed clk_set_rate() References: <1474990196-808-1-git-send-email-bgolaszewski@baylibre.com> <8136a79b-23b8-d353-8602-428cc20947f6@ti.com> In-Reply-To: --jLT0SV5vR1EVCnLLHqxnUb63HqI84MwAa Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 28/09/16 14:43, Bartosz Golaszewski wrote: > how far is far enough to emit a warning? On da850 the requested rate > is 228000000 Hz, while the calculated divider is 6, which results in > the real rate of 225000000 Hz. This is less than 1% difference - > should we take this value as reference? Good question, and I don't have a clear answer. But I think the point is just to inform the user that it's likely that his LCD won't work properly, and often LCDs are quite tolerant about the pclk. So diff less than 1% is just fine. Even 5% sounds still fine to me, perhaps even 10%. I think we just have to try something out, and adjust it if people get the message too often. Tomi --jLT0SV5vR1EVCnLLHqxnUb63HqI84MwAa-- --KcPPfFrdWmNEaufki21lhrWb1weRa5N71 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCAAGBQJX66+mAAoJEPo9qoy8lh71KpEP/1tHvuQTzxcyQgNdyp1vlaxP 7hpO0mZVDNhDzg8FuQyDcJzroLytq9HUsjkMd4jqgxDfu6RM0RWsjiAbbLfvhJ1M gw65BofXcwAyI523ksXzkFWyr+TRN3IToajvqzMisHyAF8BQVmcIlflRZUd3Satj f0oq0PTcv2oJNH8w1SD7QqDsbzOO2zoepFbMUcwS9zhBdw7IwjkXxiE62s1C8Nqb xRh1DfWz49kXUfJxUccG/9PX+2pBAlhjccd7a9mlw/bap+I3e+KSgqCWJxCEgWyR Or2cXSTsSIpsn9HNo879HCqsA4Nx7P1T5Fd8VT/FgKSZHPbhXgeSc82l/p8npZ3P DBtS1mQd0iK+tyzbNMrrisDlnbHhePEImZ5Ur1wa0iNQKa5anqoWsBeZFytR2/0K M/otupVo4wqgMS4uQ2Ri9GmgcRqJtRhe3pAf2wbIiGwF7UdFW1XxJG+u7P0SnS+O ewTuJaehXYfyDENjLB5oBFK7b8TZOaJPyGF7+f8ZfaCZx3yQmTnArCDJbL902ORO U0JaoLOn0ZLMNP5cwX/e5i9qSKCY6IsUChYLrFvyFOR3hiQw/gAXDOMVNrpuvC6S InV7u3EfbsvgwZXyI7X8V9Eeb6pn6PhFZBGNGG9GUlcy0RegzymxGtM7FAvzKa7M 3vWav1gYmPg7qBhXUWmU =UYVn -----END PGP SIGNATURE----- --KcPPfFrdWmNEaufki21lhrWb1weRa5N71--