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 1B8FBC5B543 for ; Thu, 5 Jun 2025 12:45:11 +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: MIME-Version:Content-Type:References:In-Reply-To:Date:Cc:To:From:Subject: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=G/8FocYlY0Uv/zqrEwDCoSdy/CbzWG1fyTseLizIo+s=; b=Nh6EN2gbH3pKYhhvCEQAGZ+ybd P8RMyVqsKWwXpZcTScbpKx2muCYGAhn9tiouhmMHVHtaPHUOkRBEGFiXPF3lT4lmC8NfbLjm50HGe Zq6ZnMxjgMBNPAFNgDpZCvdaXQjXrmAzvN0o364UlMYoU2SELaDg8sL8BukwE7k6Ez5lXR3ma9C38 ZNzyCVoy5RLj5aVX9QKIDhg7U75qTV73WSTyyopVLsCHkQ3pmThP6qzidr4jrcrM8AaRgDusCmJV0 i2VcqsmnsB+k7Z1ksJtAghcYv7OcMZWlRXwUPGopEeTOYhzVF/EOvc/aP4gDHdakgYtIEzRvpWc3p a8iKH3yQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uN9xv-0000000FVJc-0Ty8; Thu, 05 Jun 2025 12:45:03 +0000 Received: from bali.collaboradmins.com ([148.251.105.195]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uN9uo-0000000FUz3-0wKx; Thu, 05 Jun 2025 12:41:51 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1749127308; bh=TXksFdyyDEdsxI0qhkErvaqcJ1KZyhdNTbg4RY/u2X0=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=RkHfuRJGvu2PRqbK//2suBckGm9ffe1l5JEIk9rFWHq8Ho4RRz2CbZfNpDkefa7IR 7ivclm4GTtO/WAsZS2HTJaY74TjVDfwKebm2ARvuJdd3vAIKVtrVPG2h/vR2FNq2kE zcRAQq0rtvj6PfRxp429qLrhkyC+OTVg3VG9rZuqjkyFmGNrRajnyb6kDcH3MhUCOD 19KpyEZX03/f2wvXeGT4zUpQ6fGHHYS8V9wMRD7R4XQZgLYTudIzmboyGJcY3Vsr+c J09sj68/2iTt3a/zW0eVeUkJdp6bI7h+7XJ/YkNamWFhO9c4BbuBvM9z8XwNluKEEx ezCImSkIrcdcA== Received: from [IPv6:2606:6d00:10:5285::5ac] (unknown [IPv6:2606:6d00:10:5285::5ac]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: nicolas) by bali.collaboradmins.com (Postfix) with ESMTPSA id 9BE4A17E02B0; Thu, 5 Jun 2025 14:41:46 +0200 (CEST) Message-ID: <608f95249ff3a39efb063ab9c6a543259a7b0ac9.camel@collabora.com> Subject: Re: [PATCH v3 1/5] media: mc: add manual request completion From: Nicolas Dufresne To: Sakari Ailus , Hans Verkuil Cc: Laurent Pinchart , Mauro Carvalho Chehab , Hans Verkuil , Tiffany Lin , Andrew-CT Chen , Yunfei Dong , Matthias Brugger , AngeloGioacchino Del Regno , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, kernel@collabora.com, linux-media@vger.kernel.org, Sebastian Fricke Date: Thu, 05 Jun 2025 08:41:45 -0400 In-Reply-To: References: <20250604-sebastianfricke-vcodec_manual_request_completion_with_state_machine-v3-0-603db4749d90@collabora.com> <20250604-sebastianfricke-vcodec_manual_request_completion_with_state_machine-v3-1-603db4749d90@collabora.com> <1ccaaec7f782afc71bae5c3b0f60a786a907555c.camel@collabora.com> <8b1ed01a-b6e3-4670-a4e0-d8eee7ddc524@jjverkuil.nl> Organization: Collabora Canada Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.56.2 (3.56.2-1.fc42) MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250605_054150_420025_6D57B140 X-CRM114-Status: GOOD ( 11.59 ) 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 Hi Hans, Sakari, Le jeudi 05 juin 2025 à 09:48 +0000, Sakari Ailus a écrit : > > It's not user-triggerable, if this happens, then it is a driver bug. > > If there is a driver bug, it could well be user-triggerable, wouldn't it? > Testing may not uncover all such cases. You are both right, if the driver is not used, the warning will never trigger. I was worried of the hit of a thread safe ONCE implementation, but WARN_ONCE is simply not, it can warn few time before it stops if called from multiple CPUs at the same time. In that specific function, I can move all the checks inside the lock to make it truly once. Now its up to you, I don't have strong preference. These are driver errors, and usually quite critical. They are not bug_on simply because we have a crash free resolution, but its probably not functional anymore. Nicolas