Re: RPI4 usb, external ssd

After rsyncing the unzipped bits to /boot, it rebooted, presumably
loading /netbsd from dk1 (bsd gpt on usd).

So it's mostly ok, except for the RAM limit.  Is it a safe assumption
that NetBSD has the needed workaround described in the readme for
RPI_EFI.fd?

  * A 3 GB RAM limit is enforced __by default__, even if you are using a
    Raspberry Pi 4 model that has 4 GB or 8 GB of RAM, on account that
    the OS **must** patch DMA access, to work around a hardware bug that
    is present in the Broadcom SoC.

I have appended selected dmesg lines via egrap to show USB.  It has a
flashdrive and an ESP32 plugged in this minute.

So I guess we should document that if one uses the NetBSD image
directly, without installing RPI_EFI.fd, then xhci and maybe other
things are likely to be broken?



total memory = 2970 MB
avail memory = 2862 MB
xhci0 at acpi0 (XHC0, PNP0D10-0): mem 0x600000000-0x600000fff irq 175
xhci0: 64-bit DMA
xhci0: xHCI version 1.0
usb0 at xhci0: USB revision 3.0
usb1 at xhci0: USB revision 2.0
uhub0 at usb0: NetBSD (0x0000) xHCI root hub (0x0000), class 9/0, rev 3.00/1.00, addr 0
uhub0: 4 ports with 4 removable, self powered
uhub1 at usb1: NetBSD (0x0000) xHCI root hub (0x0000), class 9/0, rev 2.00/1.00, addr 0
uhub1: 1 port with 1 removable, self powered
uhub2 at uhub1 port 1: vendor 2109 (0x2109) USB2.0 Hub (0x3431), class 9/0, rev 2.10/4.21, addr 1
uhub2: single transaction translator
uhub2: 4 ports with 4 removable, self powered
uslsa0 at uhub2 port 3 configuration 1 interface 0
uslsa0: Silicon Labs (0x10c4) CP2102 USB to UART Bridge Controller (0xea60), rev 1.10/1.00, addr 2
ucom0 at uslsa0: Silicon Labs CP210x
umass0 at uhub2 port 4 configuration 1 interface 0
umass0: SanDisk (0x0781) Ultra USB 3.0 (0x5591), rev 2.10/1.00, addr 3
umass0: using SCSI over Bulk-Only
sd0 at scsibus0 target 0 lun 0: <SanDisk, Ultra USB 3.0, 1.00> disk removable