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 9E102C6FD1F for ; Thu, 21 Mar 2024 16:35:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id: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=MglehppJyVq8RsK+bvLjIO1gfaM7P0teBFo91+EYY6c=; b=lvz2wukFqNsCDd t8FRCy6cpSMgvEg1MgFOJwE+Wgn4G4wlZbHJ+GqXCtFWzov+9l8R56niBzRzmLw4HSZjMxG8fuClk ar2R2xAh/o850cdSZrP37DEOe9mu3GAxCwNPvG1llR4CdS6xo1mB3/kZyGzy1hMG7Pp2duVZbtve8 8FZkbaDtlfresJMb0dgXWlRuii8bonkq7drqPNDCrXfdcyYmQGSxoj8Ee9YLIBRpnJ+x+KM9iN8wy Dkd7eyR6bcuVGpqcRl4lo3J5xPRdT3otd2XO+3TGsq6MBLm5RbolIbEJoR3mncY3Ci+8HKqgBJnMC Zr8t50ILm+4mXFtzvJuA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rnLO8-00000003oZc-4AfM; Thu, 21 Mar 2024 16:35:32 +0000 Received: from out-185.mta0.migadu.com ([91.218.175.185]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rnLO6-00000003oYf-0g6R for linux-arm-kernel@lists.infradead.org; Thu, 21 Mar 2024 16:35:31 +0000 Message-ID: <9990db8b-ec05-4557-aa8c-654ed6cf9ab4@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1711038924; 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=65hUeG8OX6ql2/GX16GupJklYGDvMlauJgw18xRPFmI=; b=tNlPkdk9LOBP9JJygHsaW3toD5a18XuWBNbevoDMet1kmCy7TfmZyvz0NtGAgQbIlQrfOh bfnQhfnlzyUGbgSLOxbnzAtwlBDQY8n6olMmHKOhWs+uy8TfTPylonyX/imCUyIRlyVYFk 1jxHrHFUZNFzU0v0QclBvcCY1Vc9Ux4= Date: Thu, 21 Mar 2024 12:35:18 -0400 MIME-Version: 1.0 Subject: Re: [PATCH v2 8/8] drm: zynqmp_dp: Add debugfs interface for compliance testing Content-Language: en-US To: Tomi Valkeinen Cc: Michal Simek , David Airlie , linux-kernel@vger.kernel.org, Daniel Vetter , linux-arm-kernel@lists.infradead.org, Laurent Pinchart , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , dri-devel@lists.freedesktop.org References: <20240319225122.3048400-1-sean.anderson@linux.dev> <20240319225122.3048400-9-sean.anderson@linux.dev> <7aa16340-6a87-4110-8114-c1b863b100c9@ideasonboard.com> <76831c1e-216f-430b-bacd-2d50f352e61f@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Sean Anderson In-Reply-To: X-Migadu-Flow: FLOW_OUT X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240321_093530_509998_32F5A427 X-CRM114-Status: GOOD ( 10.16 ) 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: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org T24gMy8yMS8yNCAxMjozMSwgVG9taSBWYWxrZWluZW4gd3JvdGU6Cj4gT24gMjEvMDMvMjAyNCAx ODowOCwgU2VhbiBBbmRlcnNvbiB3cm90ZToKPj4gT24gMy8yMC8yNCAwMzo0OSwgVG9taSBWYWxr ZWluZW4gd3JvdGU6Cj4+PiBPbiAyMC8wMy8yMDI0IDAwOjUxLCBTZWFuIEFuZGVyc29uIHdyb3Rl Ogo+Pj4KPj4+PiArLyoqCj4+Pj4gKyAqIGVudW0gdGVzdF9wYXR0ZXJuIC0gVGVzdCBwYXR0ZXJu cyBmb3IgdGVzdCB0ZXN0aW5nCj4+Pgo+Pj4gImZvciB0ZXN0IHRlc3RpbmciPyA9KQo+Pj4KPj4+ PiBAQCAtMTY1NSw2ICsyMzIxLDkgQEAgc3RhdGljIHZvaWQgenlucW1wX2RwX2hwZF9pcnFfd29y a19mdW5jKHN0cnVjdCB3b3JrX3N0cnVjdCAqd29yaykKPj4+PiDCoMKgwqDCoMKgwqAgdTggc3Rh dHVzW0RQX0xJTktfU1RBVFVTX1NJWkUgKyAyXTsKPj4+PiDCoMKgwqDCoMKgwqAgaW50IGVycjsK Pj4+PiDCoMKgICvCoMKgwqAgaWYgKFJFQURfT05DRShkcC0+aWdub3JlX2hwZCkpCj4+Pj4gK8Kg wqDCoMKgwqDCoMKgIHJldHVybjsKPj4+PiArCj4+Pj4gwqDCoMKgwqDCoMKgIG11dGV4X2xvY2so JmRwLT5sb2NrKTsKPj4+PiDCoMKgwqDCoMKgwqAgZXJyID0gZHJtX2RwX2RwY2RfcmVhZCgmZHAt PmF1eCwgRFBfU0lOS19DT1VOVCwgc3RhdHVzLAo+Pj4+IMKgwqDCoMKgwqDCoMKgwqDCoMKgwqDC oMKgwqDCoMKgwqDCoMKgwqDCoCBEUF9MSU5LX1NUQVRVU19TSVpFICsgMik7Cj4+Pgo+Pj4gV2h5 IGRvIHlvdSBuZWVkIFJFQUQvV1JJVEVfT05DRSgpIGZvciBpZ25vcmVfaHBkPwo+Pgo+PiBJdCdz IG5vdCBwcm90ZWN0ZWQgYnkgZHAtPmxvY2sgc28gd2UgZG9uJ3QgaGF2ZSB0byB0YWtlIGl0IGZv cgo+PiB6eW5xbXBfZHBfaHBkX3dvcmtfZnVuYy4gQWx0aG91Z2ggbWF5YmUgd2Ugc2hvdWxkIG1h a2UgYSB2ZXJzaW9uIG9mCj4+IHp5bnFtcF9kcF9icmlkZ2VfZGV0ZWN0IHdoaWNoIGFzc3VtZXMg d2UgYWxyZWFkeSBob2xkIHRoZSBsb2NrLgo+IAo+IERvZXMgdXNpbmcgdGhlIG1hY3JvcyBzb2x2 ZSBzb21lIHBvdGVudGlhbCBpc3N1ZSwgb3IgaXMgaXQganVzdCBmb3IgZG9jdW1lbnRpbmcgdGhh dCB0aGlzIHZhcmlhYmxlIGlzIGFjY2Vzc2VkIHdpdGhvdXQgbG9jaz8KCldpdGhvdXQgdGhpcyB0 aGUgY29tcGlsZXIgaXMgZnJlZSB0byBpc3N1ZSBtdWx0aXBsZSBsb2FkcyBmb3IgdGhpcwp2YXJp YWJsZSwgd2hpY2ggY291bGQgYmUgaW5jb3JyZWN0LgoKLS1TZWFuCgoKX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KbGludXgtYXJtLWtlcm5lbCBtYWlsaW5n IGxpc3QKbGludXgtYXJtLWtlcm5lbEBsaXN0cy5pbmZyYWRlYWQub3JnCmh0dHA6Ly9saXN0cy5p bmZyYWRlYWQub3JnL21haWxtYW4vbGlzdGluZm8vbGludXgtYXJtLWtlcm5lbAo= 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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 3DA60C6FD1F for ; Thu, 21 Mar 2024 16:35:30 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7DCA210EF92; Thu, 21 Mar 2024 16:35:29 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=linux.dev header.i=@linux.dev header.b="tNlPkdk9"; dkim-atps=neutral Received: from out-189.mta0.migadu.com (out-189.mta0.migadu.com [91.218.175.189]) by gabe.freedesktop.org (Postfix) with ESMTPS id 3BD5110EF9A for ; Thu, 21 Mar 2024 16:35:26 +0000 (UTC) Message-ID: <9990db8b-ec05-4557-aa8c-654ed6cf9ab4@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1711038924; 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=65hUeG8OX6ql2/GX16GupJklYGDvMlauJgw18xRPFmI=; b=tNlPkdk9LOBP9JJygHsaW3toD5a18XuWBNbevoDMet1kmCy7TfmZyvz0NtGAgQbIlQrfOh bfnQhfnlzyUGbgSLOxbnzAtwlBDQY8n6olMmHKOhWs+uy8TfTPylonyX/imCUyIRlyVYFk 1jxHrHFUZNFzU0v0QclBvcCY1Vc9Ux4= Date: Thu, 21 Mar 2024 12:35:18 -0400 MIME-Version: 1.0 Subject: Re: [PATCH v2 8/8] drm: zynqmp_dp: Add debugfs interface for compliance testing Content-Language: en-US To: Tomi Valkeinen Cc: Michal Simek , David Airlie , linux-kernel@vger.kernel.org, Daniel Vetter , linux-arm-kernel@lists.infradead.org, Laurent Pinchart , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , dri-devel@lists.freedesktop.org References: <20240319225122.3048400-1-sean.anderson@linux.dev> <20240319225122.3048400-9-sean.anderson@linux.dev> <7aa16340-6a87-4110-8114-c1b863b100c9@ideasonboard.com> <76831c1e-216f-430b-bacd-2d50f352e61f@linux.dev> 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: 8bit X-Migadu-Flow: FLOW_OUT 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: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 3/21/24 12:31, Tomi Valkeinen wrote: > On 21/03/2024 18:08, Sean Anderson wrote: >> On 3/20/24 03:49, Tomi Valkeinen wrote: >>> On 20/03/2024 00:51, Sean Anderson wrote: >>> >>>> +/** >>>> + * enum test_pattern - Test patterns for test testing >>> >>> "for test testing"? =) >>> >>>> @@ -1655,6 +2321,9 @@ static void zynqmp_dp_hpd_irq_work_func(struct work_struct *work) >>>>        u8 status[DP_LINK_STATUS_SIZE + 2]; >>>>        int err; >>>>    +    if (READ_ONCE(dp->ignore_hpd)) >>>> +        return; >>>> + >>>>        mutex_lock(&dp->lock); >>>>        err = drm_dp_dpcd_read(&dp->aux, DP_SINK_COUNT, status, >>>>                       DP_LINK_STATUS_SIZE + 2); >>> >>> Why do you need READ/WRITE_ONCE() for ignore_hpd? >> >> It's not protected by dp->lock so we don't have to take it for >> zynqmp_dp_hpd_work_func. Although maybe we should make a version of >> zynqmp_dp_bridge_detect which assumes we already hold the lock. > > Does using the macros solve some potential issue, or is it just for documenting that this variable is accessed without lock? Without this the compiler is free to issue multiple loads for this variable, which could be incorrect. --Sean