From nobody Sun Dec 19 16:18:16 2021 X-Original-To: freebsd-arm@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id EA8211908012 for ; Sun, 19 Dec 2021 16:18:11 +0000 (UTC) (envelope-from fbsd@www.zefox.net) Received: from www.zefox.net (www.zefox.net [50.1.20.27]) (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 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "www.zefox.com", Issuer "www.zefox.com" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 4JH7Dg4nTJz3P02 for ; Sun, 19 Dec 2021 16:18:11 +0000 (UTC) (envelope-from fbsd@www.zefox.net) Received: from www.zefox.net (localhost [127.0.0.1]) by www.zefox.net (8.16.1/8.15.2) with ESMTPS id 1BJGIGwR014941 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Sun, 19 Dec 2021 08:18:16 -0800 (PST) (envelope-from fbsd@www.zefox.net) Received: (from fbsd@localhost) by www.zefox.net (8.16.1/8.15.2/Submit) id 1BJGIGva014940; Sun, 19 Dec 2021 08:18:16 -0800 (PST) (envelope-from fbsd) Date: Sun, 19 Dec 2021 08:18:16 -0800 From: bob prohaska To: MJ Cc: freebsd-arm@freebsd.org Subject: Re: Dealing with slow USB disks, was: Re: Saving environment variables in u-boot Message-ID: <20211219161816.GA14873@www.zefox.net> References: <20211217013613.GA4452@www.zefox.net> <20211218005946.GA7670@www.zefox.net> <5C44D0E6-2FF1-4EEB-B21A-83333D6FCF46@yahoo.com> <9D416106-660F-40BB-98D2-1354B53D2FEF@yahoo.com> <20211218223543.GA9484@www.zefox.net> <6105a8a6-e760-2183-72fd-92e5a60aa8df@gmail.com> <20211219005134.GA12292@www.zefox.net> <4910504f-3051-9a95-d8e4-95434042196d@gmail.com> List-Id: Porting FreeBSD to ARM processors List-Archive: https://lists.freebsd.org/archives/freebsd-arm List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-arm@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4910504f-3051-9a95-d8e4-95434042196d@gmail.com> X-Rspamd-Queue-Id: 4JH7Dg4nTJz3P02 X-Spamd-Bar: ---- Authentication-Results: mx1.freebsd.org; none X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[] X-ThisMailContainsUnwantedMimeParts: N On Sun, Dec 19, 2021 at 10:03:47PM +1100, MJ wrote: > > I would think a mechanical USB is going to pull a "lot" of power when beginning spin-up, but once rotating should be easily powered by a USB hub. Though this would not explain how it works on RPI4 unless the powered hub you're using is USB2. > That's what I thought too. I certainly didn't expect the disk to work without a powered hub. The Pi4 is a different animal; it has USB3 ports and more power available. That the mechanical disk works at all on the Pi3's USB2 ports without assistance is quite surprising. There's a table at https://hddfaqs.com/seagate-st1000lm048/ listing power requirements for the drive: Required Power For Spinup: 1000 mA Power Required (Seek): 1.7 W Power Required (Idle): 1.6 W Power Required (Standby): 0.18 W So far I haven't tried to power cycle the combo, that might not work. Still, it's been an informative exercise. Getting rid of the hub is a welcome simplification. The machine is still up after standing overnight. Thanks for writing and motivating me to try the experiment! bob prohaska >