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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 91D2FCF34B0 for ; Thu, 3 Oct 2024 14:55:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=k0KagNPwCCq2CvCaJVY5j4td7R7+u7bJKeN0d8+4kuQ=; b=IGJy2uFj8aHUqAWROnhtaj/fy2 VQ38PtWC2uE0S5i8fPR17rPhDURBZ33el3SbmQhspbHiDFcfocXpMRPR1Htbwtc4pxGsHJkJ20Gbx h0fzqCBaAYZEbXz+/8EquYn4wnBuRcOCbqDDtAPA22Bhgt3WcEnZYSWRlqHTN1foo9tMAsLpZ+Qqw QgJXeqRq/n0hs+xNH8N5sumau5TE55EFT3tHETWA0vhjjjj0EUtgBEEaIk5y3V+ef/K7zphhvOQj2 e6geZDiGgv2NafISZ/sQJAZb94Z02Rr454gA/8Gcy+TJECBR4v9wJCzUbrVwmTfNu6cCpeM78hYhV 1+10EUGw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1swNER-00000009TgK-35A0; Thu, 03 Oct 2024 14:55:08 +0000 Received: from out-177.mta1.migadu.com ([95.215.58.177]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1swNCo-00000009TNP-3vfr for linux-arm-kernel@lists.infradead.org; Thu, 03 Oct 2024 14:53:51 +0000 Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1727967201; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=k0KagNPwCCq2CvCaJVY5j4td7R7+u7bJKeN0d8+4kuQ=; b=hDBZlOYuxiAg2FRFHLCdBebeLEHo/aDXMEK0M9YPDW4wdTT6Ammtt8IvFhegcgmX0v4xBT GT7HfV//WX4/x/yyc4ojBsHm5KiysPiI/G02s0q0xY0d5haRV7UmSqRPR/xtCc8zwsz3aA lWwcDXRvf+PsfoyJ46jNqa6exaYw61s= Date: Thu, 3 Oct 2024 10:53:16 -0400 MIME-Version: 1.0 Subject: Re: [PATCH v6 0/8] drm: zynqmp_dp: IRQ cleanups and debugfs support To: Tomi Valkeinen Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, David Airlie , Michal Simek , Daniel Vetter , "Sagar, Vishal" , Laurent Pinchart , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Dmitry Baryshkov , dri-devel@lists.freedesktop.org References: <20240809193600.3360015-1-sean.anderson@linux.dev> <5e9769dd-459a-4ff3-aebb-bb7057192733@linux.dev> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Sean Anderson In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241003_075327_427852_7B05EE63 X-CRM114-Status: GOOD ( 22.97 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 10/2/24 10:50, Tomi Valkeinen wrote: > Hi, > > On 01/10/2024 21:31, Sean Anderson wrote: >> On 8/9/24 15:35, Sean Anderson wrote: >>> This series cleans up the zyqnmp_dp IRQ and locking situation. Once >>> that's done, it adds debugfs support. The intent is to enable compliance >>> testing or to help debug signal-integrity issues. > > I think the patches 1-7 look fine, and I think I can pick those already to drm-misc if you're ok with that. > > I'm a bit unsure about patch 8, probably mainly because I don't have experience with the compliance testing. > > How have you tested this? With some DP analyzer/tester, I presume? For my test setup I used an oscilloscope hooked up to the displayport output using a fixture that broke the signals out to SMA. Since the oscilloscope cannot emulate a sink, I first had the output connected to a monitor. Then I disabled HPD and reconnected the output to my fixture. This process is described in more detail in the documentation. > I think none of this (patch 8) is needed by almost anybody. Well, I found it very useful for debugging a signal integrity issue I was having. Once I could have a look at the signals it was very clear what the problem was. > Even among zynqmp_dp developers I assume it's very rare to have the > hardware for this. I wonder if it would make sense to have the debugfs > and related code behind a compile option (which would be nice as the > code wouldn't even compiled in), or maybe a module parameter (which > would be nice as then "anyone" can easily enable it for compliance > testing). What do you think? Other drivers with these features just enabled it unconditionally, so I didn't bother with any special config. > I also somehow recall that there was some discussion earlier about > how/if other drivers support compliance testing. But I can't find the > discussion. Do you remember if there was such discussion, and what was > the conclusion? With a quick look, everything in the debugfs looks > generic, not xilinx specific. The last it got discussed was back in [1], but I never got any further response. I agree that some of this is generic, and could probably be reworked into some internal helpers. But I don't have the bandwidth at the moment to do that work. --Sean [1] http://lore.kernel.org/dri-devel/cda22b0c-8d7c-4ce2-9a7c-3b5ab540fa1f@linux.dev