From nobody Sun Dec 19 22:55:30 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 CED30190C7E7 for ; Sun, 19 Dec 2021 22:55:46 +0000 (UTC) (envelope-from marklmi@yahoo.com) Received: from sonic316-55.consmr.mail.gq1.yahoo.com (sonic316-55.consmr.mail.gq1.yahoo.com [98.137.69.31]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4JHJ3P3zydz3NXD for ; Sun, 19 Dec 2021 22:55:45 +0000 (UTC) (envelope-from marklmi@yahoo.com) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1639954537; bh=UYXtW7RtT3bgMZQnZtyb6mkK5+bgahcVbV+bAjbShnc=; h=Subject:From:In-Reply-To:Date:Cc:References:To:From:Subject:Reply-To; b=adYIjRL27id3Ow52bVdSymcxF3/KL9Kq/kGTs/ZPv9T7P2Usi7PB6JXJ2bWmRG0Sx0CZqtiN2NflUBN6Euh55v3zERAjQJSO/DdT3lxP6JPjHSi+ccH6qfEaxZKZrokt+OMm72lfBGCQPO/G1ug7bUUTf8kJzMHYQmolajIXO5xHeVEYIp2uBX6ssjIhoYYY2+X10XXwm+/imhX5QVD1QgIXitzZ4+LLzzV/BfPriIcSsLio/D2+6xicEiuk04kOaRVlcXfada5aEHSGREOULBZVZTjKo7PbMu2fppHi3sEHxaZJvqYrF2shDkjJ/7cB77cULdvU1tG7UZ7SAoXjyg== X-SONIC-DKIM-SIGN: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1639954537; bh=qyC3o3UqR7ZlOBoywn2blnvRe8QkouAz3AjYQP3FNQc=; h=X-Sonic-MF:Subject:From:Date:To:From:Subject; b=JtSt6686SaLiIeVxfusdvbqMDax3TDC5UHZIyrtbWYgv0Wjy/TSe4zyYhuSqGHLvcKboiHKtto2dvIdXn2RisGKU4Mskyricxl+4U9k8xcCAiZwx4+HJaslxHlnkgmvG4RwcmoRf/5+UCvGTlBvLigB8ImRT9k+jZuVrA/gO2cYzOiFShgkfP0IvQvqA7bnsd3EETOBk7zjjz2hN9mWuUkC15k/IrWZyYJjuB8KYX6scWqLyntIdeMOtCu4AdpIgP2cOHsG5dyjgoeb8DWVzHfXToki6ReclxthTGPZN9Vn3aO/PpKw1h2MnlApDPG3mtvZj92XCDw/iNzvjQgD1iw== X-YMail-OSG: fGFP4tMVM1lUmVmv_N1djeLW85BZD5s.GPweKZUqv6IlpAO8Fx34usHT7bpJKR0 S9EdgV3Gd9l1YvZT_4E4veXVlRT7xVPpM2cC9WRwogb2C3wzbgyNP2dorhOpsrNKG2uGNPCE.RqK t1XgSaay7rADxT5Wtwbru3WFVBpMBcZo22waduPFQmdibiYt2.sOA_FimxvZ6cuPCe9pc0hetVxb 9O5pp3hhuxMJdtG9dmZQz_EApnTw1.pTy8eQgDv69GU_nyXFQGw2dp2iO31jfi.K9SsD5p66mAHu IXxe_3RqFMJlOHzbZfCWzIGmr5uuHP9_EhEVFEMXbybHWbCfcV5BO8gUOyuFjCp4zAS3RCByQZn3 mVaoro.sGWyf3XboKbqbqb7V2e7pcS1DHXUbd4FkFtvwfCnr4_MY9nUQdJmooN9q3.gZGQ5tM9Cd HCPKDowqmKUiLKeeX8ssNKWrrclJ4gD5dIJKoMXJMe0tEG_zSQcVocqA_FhgjQcPIQE354ncRK4L oPTIVna0EOZ7CqUhSZAKf7_7PHkRihgc.UazmfeWzJvtpHJRHmsLApoFRijyal3SpR8G5e60En5. 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Though this would not explain how it works on RPI4 unless the = powered hub you're using is USB2. >>>=20 >> 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. >=20 > See here: = https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#typi= cal-power-requirements > It mentions 1.2A, which covers your load, but, I would suspect if you = attached, for example, a USB 'thumb' drive or other devices you would = cause problems. Unfortunately there is more involved: USB2's standard indicates 500mA (0.5A) at maximum on 1 standard USB2 port. It takes 2 USB2 ports to get to a total of 1000mA (1A) (unless a port is designed to go beyond the standard). To my knowledge most RPi*'s are not designed to support more than the standard USB2 power on any of its USB2 ports. (The 3A+, Zero W/WH, and Zero are apparently exceptions, depending on the power supply used and such.) There are drive cases with support for external power supplies that could be used, so long as the drive is powered before the RPi*. There may be adapters that plug into more than one USB2 port in order to draw extra power. Then there is the use of SSD's instead of spinning rust: they tend to not have the large surge currents involved. But the combination of spinning rust, bus power only, and a single USB2 port for power is fairly generally unreasonable due to the 500mA limitation. This is true even if the total USB power that the system provides is much larger. >> 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 >=20 >=20 > The total draw capable will inevitably come down to the power supply = unless, as you know, you use a powered hub (and even then, it depends on = the hub's power output abilities). >=20 =3D=3D=3D Mark Millard marklmi at yahoo.com