Date: Sun, 30 May 2021 18:54:29 -0500 From: William Carson via freebsd-arm <freebsd-arm@freebsd.org> To: Mark Millard <marklmi@yahoo.com> Cc: freebsd-arm <freebsd-arm@freebsd.org> Subject: Re: Boot from USB on RPi4 8GB? Message-ID: <FA5F90A1-0E02-4CC8-A860-38C62E0ED93E@dsllsn.net> In-Reply-To: <E267DA59-F294-40D4-B2DB-4E6DF8C87DCF@yahoo.com> References: <4F3EE8D2-649B-4522-AD5A-7C308291802F@dsllsn.net> <43FAEEAC-EE36-4810-88AA-FF82AFBCC128@yahoo.com> <2F58272B-BD9C-464B-9A98-BF638971BA86@dsllsn.net> <D82CA5FE-1755-4D38-928E-B8234A4F38D4@yahoo.com> <E267DA59-F294-40D4-B2DB-4E6DF8C87DCF@yahoo.com>
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> On May 30, 2021, at 4:08 PM, Mark Millard <marklmi@yahoo.com> wrote: >=20 > On 2021-May-30, at 13:50, Mark Millard via freebsd-arm <freebsd-arm at = freebsd.org> wrote: >=20 >> On 2021-May-30, at 10:59, William Carson via freebsd-arm <freebsd-arm = at freebsd.org> wrote: >>=20 >>>> . . . >>>> I use a USB3 SSD that has small enough power requirements >>>> to not require a powered hub. (I also use a 5.1V 3.5A >>>> power supply as part of that context.) I've never tried >>>> spinning rust or higher powered USB3 media. >>=20 >> I view the power supply that I use as just giving a little >> more margin, not as a way to increase what the devices >> total to. >>=20 >>> . . . I'm not sure what's considered "high powered" but the Samsung = tech specs say this particular model uses 5.7 W on average and 10.0 W = maximum. But it does seem curious that the Raspberry PI OS will boot = this disk without issue, so I don't think it's the drive. I also tried a = Samsung 950 PRO using a different enclosure (QNINE NVME Enclosure, M.2 = PCIe SSD (M Key) to USB 3.0 External Case), but it behaved the same. >> . . . >>=20 >> Then you need to use a powered hub for that device. >=20 > I should have just referred to independent power. You > had written: >=20 > QUOTE > I'm trying to use a SAMSUNG (MZ-V7E500BW) 970 EVO SSD 500GB - M.2 = NVMe, attached via the Geekworm X872 M.2 NVMe 2280/2260/2242/2230 SSD = Expansion Board. > END QUOTE >=20 > = https://geekworm.com/products/raspberry-pi-4-x872-m-2-nvme-2280-2260-2242-= 2230-ssd-expansion-board >=20 > shows that it has its own power connector and has an image > that says "please power x872 via DC Jack of XH2.54 connector > if SSD is not recognized or low power". Later text on the > page says: >=20 > QUOTE > Specifications: > Power Supply > =E2=80=A2 5Vdc +/-5% , Powered by Raspberry Pi USB port > =E2=80=A2 5Vdc via DC power jack or XH2.5 connector, Extra power = for the SSD > END QUOTE >=20 > So, if I gather right, you need to connect a power > supply to the X872 and another to the RPi4B. >=20 > Another image says "Note: NOT recommended to use SAMSUNG SSD, > if use SAMSUNG SSD, please close WiFi". Later text on the page > says the same. A-ha, indeed. I just noticed that as well. I've gone ahead and ordered a = supplementary power supply and a lower-power NVMe to do more testing. = I'll send an update once I've received and tested them. Thank you for hopefully pointing me in the right direction. > = https://www.raspberrypi.org/documentation/hardware/raspberrypi/power/READM= E.md >> lists: >>=20 >> "Maximum total USB peripheral current draw" as: 1.2A , >> which at 5.1V is 6W. >>=20 >> That figure is the total for all USB devices attached >> that are not powered independently. >>=20 >> That document also says that a 5.1V supply is required, >> not 5V. >>=20 >> The power supply that the RPi folks supply is 5.1V @ 3A >> or 15.3W. Even the 5.1V 3.5A power supply that I use >> only multiplies out to 17.85W. >=20 > =3D=3D=3D > Mark Millard > marklmi at yahoo.com > ( dsl-only.net went > away in early 2018-Mar) >=20 >=20 >=20 > =3D=3D=3D > Mark Millard > marklmi at yahoo.com > ( dsl-only.net went > away in early 2018-Mar) >=20
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