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 X-Spam-Level: X-Spam-Status: No, score=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 267D6C433E0 for ; Fri, 19 Feb 2021 16:39:53 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id E2A9A64DF0 for ; Fri, 19 Feb 2021 16:39:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E2A9A64DF0 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 1B5D06EB73; Fri, 19 Feb 2021 16:39:52 +0000 (UTC) Received: from z11.mailgun.us (z11.mailgun.us [104.130.96.11]) by gabe.freedesktop.org (Postfix) with ESMTPS id 2B24A6E060 for ; Fri, 19 Feb 2021 16:39:48 +0000 (UTC) DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1613752790; h=Message-ID: References: In-Reply-To: Subject: Cc: To: From: Date: Content-Transfer-Encoding: Content-Type: MIME-Version: Sender; bh=bGYuBowdCAf1ux6PDCOPxHG/ip7+T+wrGkBIdOPIiaM=; b=FsiE3pfYXy94eKqDV2covxdXyzvcLXRwxniJjMOmDB8jTsJBN3W7e+tagkMahZClXV7hG8/f XQpvHMQbsiHCGa+RGEOLnDJo4aZO4QzrFnjBSxGBWU4wwlaG+Fzl9QLrtBUJhy9Zmi7oblBo SwyRK301ITNa2LSS5D9gCeYP/W8= X-Mailgun-Sending-Ip: 104.130.96.11 X-Mailgun-Sid: WyJkOTU5ZSIsICJkcmktZGV2ZWxAbGlzdHMuZnJlZWRlc2t0b3Aub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n04.prod.us-west-2.postgun.com with SMTP id 602fe9cb7237f827dce4a275 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Fri, 19 Feb 2021 16:39:39 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 39DAFC43463; Fri, 19 Feb 2021 16:39:39 +0000 (UTC) Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: khsieh) by smtp.codeaurora.org (Postfix) with ESMTPSA id 89D79C433CA; Fri, 19 Feb 2021 16:39:38 +0000 (UTC) MIME-Version: 1.0 Date: Fri, 19 Feb 2021 08:39:38 -0800 From: khsieh@codeaurora.org To: Stephen Boyd Subject: Re: [PATCH v2 2/2] drm/msm/dp: add supported max link rate specified from dtsi In-Reply-To: <161368935031.1254594.14384765673800900954@swboyd.mtv.corp.google.com> References: <1613681704-12539-1-git-send-email-khsieh@codeaurora.org> <161368935031.1254594.14384765673800900954@swboyd.mtv.corp.google.com> Message-ID: <7af07dcacd5b68087cc61e467e9c57ea@codeaurora.org> X-Sender: khsieh@codeaurora.org User-Agent: Roundcube Webmail/1.3.9 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: , Cc: freedreno@lists.freedesktop.org, airlied@linux.ie, linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, abhinavk@codeaurora.org, tanmay@codeaurora.org, aravindh@codeaurora.org, sean@poorly.run Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 2021-02-18 15:02, Stephen Boyd wrote: > Quoting Kuogee Hsieh (2021-02-18 12:55:04) >> Allow supported link rate to be limited to the value specified at >> dtsi. If it is not specified, then link rate is derived from dpcd >> directly. Below are examples, >> link-rate = <162000> for max link rate limited at 1.62G >> link-rate = <270000> for max link rate limited at 2.7G >> link-rate = <540000> for max link rate limited at 5.4G >> link-rate = <810000> for max link rate limited at 8.1G >> >> Changes in V2: >> -- allow supported max link rate specified from dtsi > > Please don't roll this into the patch that removes the limit. The > previous version of this patch was fine. The part that lowers the limit > back down should be another patch. > > We rejected link-rate in DT before and we should reject it upstream > again. As far as I can tell, the maximum link rate should be determined > based on the panel or the type-c port on the board. The dp controller > can always achieve HBR3, so limiting it at the dp controller is > incorrect. The driver should query the endpoints to figure out if they > want to limit the link rate. Is that done automatically sometimes by > intercepting the DPCD? ok, i will roll back to original patch and add the second patch for max link rate limited purpose. panel dpcd specified max link rate it supported. At driver, link rate is derived from dpcd directly since driver will try to use the maximum supported link rate and less lane to save power. Therefore it is not possible that limit link rate base on dpcd. AS i understand we are going to do max link rate limitation is due to old redriver chip can not support HBR3. How can I acquire which type-c port on the board so that I can trigger max link rate limitation? _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel