From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-176.mta1.migadu.com (out-176.mta1.migadu.com [95.215.58.176]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F250F14F135 for ; Fri, 25 Oct 2024 14:58:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.176 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729868292; cv=none; b=gGx78t+bopDWvLsX7aNlLnhqcf2p6IA58J7ZMsQ5hRZsSuWr38qpUE2/ARwso/lgL5BCwO2XjSmh+JbuH4jdWWORPoAm5vxVxSiCWJ93qllPvFhNATFmUMGtzPrOHJPr7hE0/dqI04Vw8HgPFSdNU1A4ekpvaUNmQ7Qye0n6Nug= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729868292; c=relaxed/simple; bh=g3MfoZxhecfi4HZ5CyZhoCkqBJe/YJdi/vBp0g2shGI=; h=Message-ID:Date:MIME-Version:Subject:From:To:Cc:References: In-Reply-To:Content-Type; b=J7UttEMz4hLdqiXmtrOpGEi+76VoHayaK2re/86rWofT0BGZrQUk2vS/7vukDhkl02Md6yaY73mnm8y7qPnpqtqQ1ZNhBUzF7xDyjWbVNgirxSqDGbqkoVeTS+hSD2uO80GL8CGd1/TCSmYwJtScK8NtVnPYceG+wkhx7Pe+zPs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=lsT0ohrO; arc=none smtp.client-ip=95.215.58.176 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="lsT0ohrO" Message-ID: <07766e5e-6009-4b8e-8a50-30ba0fe763f5@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1729868285; 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=a8cGWjeBVtubT1nOUtGsNOA8VZMw6hKLHJizMjgK7rM=; b=lsT0ohrOh5E5xFM4/dj8E2d6LS9jzHhErfRZvWVngnIdLZIK7DuzuMzxTL+5FIV4LeCWN+ U/20Ma87/13Nzno2oI+HQ5PtOK5L7+Jks9xkOZWaXhupqk0lEsFH/AtfUIT+Sa7/dD0CJJ yt+rOq5RPn/O0mA6h1enlPz24Aq4YXI= Date: Fri, 25 Oct 2024 10:58:00 -0400 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH v6 0/8] drm: zynqmp_dp: IRQ cleanups and debugfs support X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Sean Anderson 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 In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT Hi Tomi, On 10/3/24 10:53, Sean Anderson wrote: > 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 Does this all make sense to you? At the moment I don't believe I have any changes I need to resend for (although this series is archived in patchwork [1] for some reason). --Sean [1] https://patchwork.kernel.org/project/dri-devel/list/?series=878338&archive=both