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

Sebastian Sumpf Sebastian.Sumpf at
Mon Apr 15 10:18:19 CEST 2019

Hello Tomasz,

On 4/15/19 9:42 AM, Christian Helmuth wrote:
> 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?

great findings. I didn't know about address ranges on Rpi's and
definitely will have a look at them when fixing issue 3247 [1].




Sebastian Sumpf
Genode Labs ·

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

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