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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A2ED1C433FE for ; Wed, 16 Feb 2022 02:16:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241505AbiBPCRC (ORCPT ); Tue, 15 Feb 2022 21:17:02 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:42280 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235143AbiBPCRC (ORCPT ); Tue, 15 Feb 2022 21:17:02 -0500 Received: from alexa-out-sd-01.qualcomm.com (alexa-out-sd-01.qualcomm.com [199.106.114.38]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BFB17BF97D; Tue, 15 Feb 2022 18:16:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; i=@quicinc.com; q=dns/txt; s=qcdkim; t=1644977810; x=1676513810; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=Nf4w5alxBcN8IhONDyerdZKXyOFUjVM7GbSWZYsTNBk=; b=nXKXip3jAsfLyNW3FGt+5mOPybeoGQNDA0x3HY5yP6DK+CPkAAK4ihYt Dkyh9vZksjGyn/78c7hrilhApIhd+VkjyeDXKQeoMtKZDh3PZWkqSWtzW OGZP38rKIn1NMd1C+2HrUr8nPjSvLeNfTt8tzutLfN8QK7U/3JiwXxmgL E=; Received: from unknown (HELO ironmsg04-sd.qualcomm.com) ([10.53.140.144]) by alexa-out-sd-01.qualcomm.com with ESMTP; 15 Feb 2022 18:16:50 -0800 X-QCInternal: smtphost Received: from nasanex01c.na.qualcomm.com ([10.47.97.222]) by ironmsg04-sd.qualcomm.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Feb 2022 18:16:50 -0800 Received: from nalasex01a.na.qualcomm.com (10.47.209.196) by nasanex01c.na.qualcomm.com (10.47.97.222) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.15; Tue, 15 Feb 2022 18:16:49 -0800 Received: from [10.111.168.21] (10.80.80.8) by nalasex01a.na.qualcomm.com (10.47.209.196) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.922.19; Tue, 15 Feb 2022 18:16:48 -0800 Message-ID: <7b33c826-b141-c6a2-b0eb-18b99ceeda24@quicinc.com> Date: Tue, 15 Feb 2022 18:16:45 -0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.5.1 Subject: Re: [Freedreno] [PATCH v2 2/2] drm/msm/dpu: Add SC8180x to hw catalog Content-Language: en-US To: Bjorn Andersson CC: Dmitry Baryshkov , , , , References: <20220215043353.1256754-1-bjorn.andersson@linaro.org> <20220215043353.1256754-2-bjorn.andersson@linaro.org> <6a3ef247-b26b-d505-cd85-92fb277163dd@quicinc.com> From: Abhinav Kumar In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01a.na.qualcomm.com (10.52.223.231) To nalasex01a.na.qualcomm.com (10.47.209.196) Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On 2/15/2022 6:03 PM, Bjorn Andersson wrote: > On Tue 15 Feb 19:34 CST 2022, Abhinav Kumar wrote: > >> >> >> On 2/15/2022 4:20 PM, Dmitry Baryshkov wrote: >>> On Tue, 15 Feb 2022 at 23:21, Abhinav Kumar wrote: >>>> On 2/15/2022 10:42 AM, Dmitry Baryshkov wrote: >>>>> On Tue, 15 Feb 2022 at 20:42, Abhinav Kumar wrote: >>>>>> On 2/15/2022 9:28 AM, Bjorn Andersson wrote: >>>>>>> On Tue 15 Feb 11:14 CST 2022, Abhinav Kumar wrote: >>>>>>>> On 2/14/2022 8:33 PM, Bjorn Andersson wrote: >>>>>>>>> From: Rob Clark > [..] >>>>> (thus leading us to cases when someone would forget to add INTF_EDP >>>>> next to INTF_DP) >>>>> >>>>> Also, if we are switching from INTF_DP to INTF_EDP, should we stop >>>>> using end-to-end numbering (like MSM_DP_CONTROLLER_2 for INTF_5) and >>>>> add a separate numbering scheme for INTF_EDP? >>>>> >>>> We should change the controller ID to match what it actually is. >>>> >>>> Now that you pointed this out, this looks even more confusing to me to >>>> say that MSM_DP_CONTROLLER_2 is actually a EDP controller because >>>> fundamentally and even hardware block wise they are different. >>> >>> So, do we split msm_priv->dp too? It's indexed using >>> MSM_DP_CONTROLLER_n entries. >>> Do we want to teach drm/msm/dp code that there are priv->dp[] and >>> priv->edp arrays? >> >> ok so now priv->dp and priv->edp arrays are also in the picture here :) >> >> Actually all these questions should have probably come when we were figuring >> out how best to re-use eDP and DP driver. >> >> Either way atleast, its good we are documenting all these questions on this >> thread so that anyone can refer this to know what all was missed out :) >> >> priv->dp is of type msm_dp. When re-using DP driver for eDP and since >> struct msm_dp is the shared struct between dpu and the msm/dp, I get your >> point of re-using MSM_DP_CONTROLLER_* as thats being use to index. >> >> So MSM_DP_CONTROLLER_* is more of an index into the DP driver and not really >> a hardware indexing scheme. >> >> If we split into two arrays, we need more changes to dpu_encoder too. >> >> Too instrusive a change at this point, even though probably correct. >> > > I'm sorry, but performing such a split would create a whole bunch of > duplication and I don't see the reasons yet. Can you please give me an > example of when the DPU _code_ would benefit from being specifically > written for EDP vs DP? > > Things where it doesn't make sense to enable certain features in > runtime - but really have different implementation for the two interface > types. > Like I have mentioned in my previous comment, this would be a big change and I am also not in favor of this big change. >> But are you seeing more changes required even if we just change INTF_DP to >> INTF_eDP for the eDP entries? What are the challenges there? >> > > What are the benefits? In terms of current code, again like I said before in my previous comments several times I do not have an example. I was keeping the separation in case in future for some features we do need to differentiate eDP and DP. Somehow I also feel this change and below are interlinked that way. https://patchwork.freedesktop.org/patch/473871/ The only reason we need this change is because both eDP and DP use DRM_MODE_ENCODER_TMDS and specifying the intf_type directly will clear the confusion because DRM_MODE_ENCODER_DSI means DSI and DRM_MODE_ENCODER_VIRTUAL means Writeback but DRM_MODE_ENCODER_TMDS can mean DP OR eDP interface. The ambiguity was always for eDP and DP. That led to the discussion about the INTF_* we are specifying in the dpu_hw_catalog only to find the discrepancy. So now by clearing that ambiguity that change makes sense. That discussion trickled into this one. > > Regards, > Bjorn