usb_drv error -92 for RPi | Genode 18.05 with Fiasco.OC 79

Christian Helmuth christian.helmuth at
Mon Apr 15 09:42:57 CEST 2019

Hello Tomasz,

On Sat, Apr 13, 2019 at 18:40:59 CEST, Tomasz Gajewski wrote:
> On rpi3 (and others) there is a difference between bus addresses and
> physical addresses. In [1] I made a "brutal" fix working for
> rpi3. It is definitely not the final one as it is not just for rpi.

Great finding! I instantly had a look into the BCM2835/7 ARM
Peripherals manuals and it seems the 0x40000000 bus address range is
specified as L2-cache coherent alias of the first 256 MiB SDRAM, which
are also mapped uncached to bus address 0xc0000000.

Do you agree that from this specification 0xc0000000 should also work
for DMA-based devices on Rpi1?

Christian Helmuth
Genode Labs · · /ˈdʒiː.nəʊd/

Genode Labs GmbH · Amtsgericht Dresden · HRB 28424 · Sitz Dresden
Geschäftsführer: Dr.-Ing. Norman Feske, Christian Helmuth

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