> It's been a long time since I've used FIT, but I seem to remember that > it was simply a device tree-based description of a file format. As such > couldn't you add an additional property to the configuration entry that > the bootloader could match on? That would avoid the need to parse an > embedded device tree and it might be useful to keep variants for the > same board in the same FIT image. Yes, I suppose something like that would be possible, however it's not just depthcharge that matches to configurations based on the compatible string within the configuration's FDT blob, this is the convention U-Boot uses as well when booting FIT images. > Perhaps you can explain a little more what the use-cases are. For > example how are people suppose to run an upstream kernel on one of these > Chromebooks? There are a few ways you could run an upstream kernel: 1) Building your own verified-boot-wrapped FIT image and replacing the existing one using tools found in the ChromiumOS tree [0]. This is the workflow must of our developers use when working on product kernels, but could just as easily be done with an upstream kernel. 2) Using U-Boot, either through the built-in legacy mode payload (Ctrl-L at the developer screen) or by replacing the vboot-wrapped FIT image with one that has U-Boot as a payload rather than a kernel [1]. 3) If you're willing to flash your own firmware to the device, you can build netboot-enabled firmware form the ChromiumOS tree that will load a FIT image over the network. This is the most flexible, as it doesn't require the root device to be partitioned in any particular way and allows you to boot non-ChromeOS distributions (e.g. Ubuntu). This is what Dylan and I usually do when working on upstream kernels. > How does dual-booting work? You could dual-boot with the legacy-mode U-Boot, described above. > Does the user get a menu to choose a configuration they want to boot if > multiple entries are compatible with the detected board? IIRC depthcharge will just pick the first one if there are multiple exact matches. [0] http://www.chromium.org/chromium-os/how-tos-and-troubleshooting/kernel-faq#TOC-How-to-quickly-test-kernel-modifications-the-fast-way- [1] http://www.chromium.org/chromium-os/u-boot-porting-guide/using-nv-u-boot-on-the-samsung-arm-chromebook#TOC-Installing-nv-U-Boot-chained-U-Boot-method- -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
