On Tue, Jul 23, 2019 at 12:00:04PM +0100, Michael Brown wrote: > > Why is this patch useful? > > I understand the problem, but we include the .dtb from our own > > edk2-non-osi tree. And it seems that device tree already provides an > > alias to support both: > > https://github.com/tianocore/edk2-non-osi/blob/master/Platform/RaspberryPi/RPi3/DeviceTree/bcm2710-rpi-3-b.dts > > > > Would it be more useful to warn loudly if "ethernet" isn't present? > > (And just *replace* ethernet[0] with ethernet below.) > > The device tree can also be provided by the VC4 firmware, e.g. with a > config.txt containing e.g. > > device_tree_address=0x10000 > device_tree_end=0x20000 > device_tree=bcm2710-rpi-3-b-plus.dtb
Ah, right. > It is also possible to omit the explicit "device_tree=..." and have just > > device_tree_address=0x10000 > device_tree_end=0x20000 > > This configuration will cause the VC4 firmware to automatically load the > appropriate device tree file. I have tested that this allows me to boot > from a 3B or 3B+ using a single SD card image that contains all of the .dtb > files from > > https://github.com/raspberrypi/firmware/tree/master/boot > > These "official" raspberrypi-firmware .dtb files are built from the stock > Linux kernel .dts files, and contain only "ethernet0". *facepalm* > To address your specific questions: > > > Why is this patch useful? > > It allows us to boot using the "official" .dtb files without any unexpected > behaviour. > > This in turn allows us to boot with the VC4 firmware automatically selecting > the appropriate .dtb file for the hardware. This is extremely useful when > trying to provide a single SD card image that will work on a wide range of > hardware. Yeah, understood. I just have a poor understanding of the esoteric boot architecture of the Pis. > > Would it be more useful to warn loudly if "ethernet" isn't present? > > (And just *replace* ethernet[0] with ethernet below.) > > This would also solve the problem. I would find it mildly surprising > behaviour if I were debugging around it, since the "official" .dtb files > have moved in the other direction (going from "ethernet" to "ethernet0"), > but I would not expect it to break anything. > > Another option would be to have UpdateMacAddress() ensure that both > "ethernet" and "ethernet0" aliases exist. Yeah, that would probably be my preferred option. > I am happy to work up a new version of the patch: just let me know which > option you prefer. As mentioned. And thank you for the explanation. Best Regards, Leif -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#44244): https://edk2.groups.io/g/devel/message/44244 Mute This Topic: https://groups.io/mt/32529756/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
