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 D6B09C433FE for ; Thu, 3 Nov 2022 12:07:45 +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:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=QsrdRXfMWYL/lMIYWhPsuUaOMQUNs5HaBLMDnXy01MU=; b=sHlaJ0GTpjqpQS uDcx0GIvB7Lxp0qpdN+rfNz39UARA4wGYJ34TpQg7RjXezcWkUiRaLpVkj5o8Yavvu6yzEI8FsRMW fRFJTl3MgZa4xDlupYNWJjZwPdsdHqTGUpaO7xk+2p9ANkI4xd7iN3WMInkycVsS15zRvu/yy3DGk P8EN+a/q4IOuFSkfjVLbc0iA4Kj4alfWIpgXyODVgmuom2PtyxPi7IVw0AcI4Yzl86VJ7J79jZvaK O4OuXUb1H01PpnXnlN7cMmr0FNzASK+yu7gmHlTlgNUE2OGdwVc3rBPnYSsIOgKDedbFkJxYR1JjT PUKI72zQV2+UQZqwwQJQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oqYzY-00HGkJ-HG; Thu, 03 Nov 2022 12:06:40 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oqYzS-00HGiK-FK for linux-arm-kernel@lists.infradead.org; Thu, 03 Nov 2022 12:06:38 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9C06D1FB; Thu, 3 Nov 2022 05:06:33 -0700 (PDT) Received: from e120937-lin (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 974343F703; Thu, 3 Nov 2022 05:06:25 -0700 (PDT) Date: Thu, 3 Nov 2022 12:06:15 +0000 From: Cristian Marussi To: Sudeep Holla Cc: Florian Fainelli , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, james.quinlan@broadcom.com, Jonathan.Cameron@huawei.com, etienne.carriere@linaro.org, vincent.guittot@linaro.org, souvik.chakravarty@arm.com, wleavitt@marvell.com, peter.hilber@opensynergy.com, nicola.mazzucato@arm.com, tarek.el-sherbiny@arm.com, quic_kshivnan@quicinc.com Subject: Re: [PATCH v4 0/11] Introduce a unified API for SCMI Server testing Message-ID: References: <20221019204626.3813043-1-cristian.marussi@arm.com> <20221103112147.rq2v7dwte577kmb4@bogus> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20221103112147.rq2v7dwte577kmb4@bogus> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221103_050634_657291_D5E5937F X-CRM114-Status: GOOD ( 30.02 ) 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="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Nov 03, 2022 at 11:21:47AM +0000, Sudeep Holla wrote: > On Fri, Oct 28, 2022 at 07:38:25PM -0700, Florian Fainelli wrote: > > Hi Christian, > > > > On 10/19/2022 1:46 PM, Cristian Marussi wrote: > > [snip] > > > > > In V2 the runtime enable/disable switching capability has been removed > > > (for now) since still not deemed to be stable/reliable enough: as a > > > consequence when SCMI Raw support is compiled in, the regular SCMI stack > > > drivers are now inhibited permanently for that Kernel. > > > > For our platforms (ARCH_BRCMSTB) we would need to have the ability to start > > with the regular SCMI stack to satisfy if nothing else, all clock consumers > > otherwise it makes it fairly challenging for us to boot to a prompt as we > > purposely turn off all unnecessary peripherals to conserve power. We could > > introduce a "full on" mode to remove the clock provider dependency, but I > > suspect others on "real" silicon may suffer from the same short comings. > > > > Fair enough. But if we are doing SCMI firmware testing or conformance via > the $subject proposed way, can these drivers survive if the userspace do > a random or a torture test changing the clock configurations ? Not sure > how to deal with that as the intention here is to do the testing from the > user-space and anything can happen. How do we avoid bring the entire system > down while doing this testing. Can we unbind all the drivers using scmi on > your platform ? I guess no. Let me know. > > > Once user-space is reached, I suppose we could find a way to unbind from all > > SCMI consumers, and/or ensure that runtime PM is disabled, cpufreq is in a > > governor that won't do any active frequency switching etc. > > > > What do you think? > > Yes, Cristian always wanted to support that but I am the one trying to > convince him not to unless there is a strong requirement for it. You seem > to suggest that you have such a requirement, but that just opens loads of > questions and how to we deal with that. Few of them are as stated above, I > need to recall all the conversations I had with Cristian around that and why > handling it may be bit complex. :D ... I really even more like the idea of enabling on demand full coexistence so that I completely delegate to the users to manually deal with possible interferences at runtime and drop any liabilities if someone shoots himself in the foot :P ... jokes apart I'll post today a V5 with a few fixes and and an optional coexistence mode so that Florian can experiment and see how much is feasible to operate in this way by manually unbinding/re-configuring SCMI behaviour at runtime before starting tests and not kill the system on something like ARCH_BRCMSTB platforms. Thanks, Cristian _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel