Hi Paul, > Am 29.03.2019 um 11:27 schrieb Paul Boddie <[email protected]>: > > On Friday 29. March 2019 08.57.22 H. Nikolaus Schaller wrote: >> >>> Am 27.03.2019 um 17:51 schrieb H. Nikolaus Schaller <[email protected]>: >>> >>> >>> >>> So I have ordered one some minutes ago. The key idea was that I expect to >>> get a board where I can more easily test and debug the MIPS variant of >>> LetuxOS incl. kernels. And then this might help to get it onto the >>> MipsBooks/Letux 400... >> >> It already arrived yesterday. > > Things happen fast where you are! I think my board was shipped from the USA > and although it did enter the country fairly quickly after that, I ended up > arguing with the courier about the tax applied to the "free shipping" for > several weeks afterwards.
Mine came through UPS from the UK. Nobody has an idea how this will run in the future... > >> Now I did power it on - and I am really impressed. It is the first board >> I have seen where there is 3D-GPU support included in the preinstalled >> NAND image. It starts with Xfce, Debian 7.5 (Wheezy), Kernel 3.0.8 and >> as said SGX drivers are included and loaded. Running the sgx_clipblit_test >> can be done immediately from the command line. This is where LetuxOS >> on omap3 still fails... > > It sounds like they did a good job on the default software. Unfortunately for > me, neither my monitor nor another one - both supporting DVI via an adapter - > could support the default resolution, which was particularly odd for the > second monitor. Although I recompiled the driver to use a different > resolution, I think I just decided to switch kernels in the end. > > It is worth noting that modern GCC versions do not like the kernel code from > the 3.0.8 era (nor the U-Boot version being used), and there are some fixes > needed (in include/linux/compiler-gcc.h), but I am sure you have seen this > before. Also worth noting from looking at the drivers is that some of them > were fixed up to be less like vendor code and more like normal kernel code in > 3.18, so the HDMI support is rather different. > > I also found from experiments that the I2C support is unreliable, although > the > Linux driver usually manages to get the display resolution over I2C just > fine. > Apparently, previous Ingenic SoCs also have reliability issues with the I2C > support. > >> So far I only have these observations: >> * there is no heartbeat so unless a monitor is connected it is difficult to >> tell if the board is running > > The rather bright LEDs tend to flash a lot, but that appears to be related to > MMC/SD activity. I have used the Flash image only and not yet the SD card reader. > >> * the apt/sources.list is outdated and points to server names no longer >> available (Debian rearranges things every now and then) > > Another thing that probably won't affect you is that most of the online > resources for this board are gone now. But pity the people who bought the > CI40 > for IoT and for use with some cloud-based service provided by Imagination! > >> * I had to change the keyboard layout > > This is something I should have mentioned, but it is part of the usual Debian > configuration procedure: > > dpkg-reconfigure keyboard-configuration > > Also things like the locales. Since there's no battery on the board (arguably > reasonable given the Ethernet and WLAN support, perhaps also better for the > planet), the RTC needs updating every boot-up, but the distribution seems to > take care of that using NTP, I think. Well it was easier to use the Xfce Settings... menu. Because I already had problems typing the "-" character for something like "dpkg-reconfigure keyboard-configuration". > >> * the board has a standard-SD slot (but I have enough adapters) >> * the Mini-USB/OTG port is installed vertically - funny :) > > There is some weird stuff with the OTG connector: > > https://www.elinux.org/CI20_Hardware#USB_mini-OTG_connector Ok, this is an important warning!!! > >> * it is not clear how where and how to connect an RS232 port - but kernel >> boot log is shown on screen > > I use UART0 via pins 6, 8 and 10 of the primary expansion header: > > https://www.elinux.org/CI20_Hardware#Primary_expansion_header > > I use a USB-to-UART adapter like this: > > https://shop.pimoroni.com/products/usb-to-uart-serial-console-cable Yes, I have several of such things. > > I think that the U-Boot prompt is only shown via the UART. That would be expected. U-Boot does not know displays (with some exceptions like GTA04 or OpenPandora). > >> So in summary it was a good decision to get one :) > > They could have done with customers like you when it first came out, I'm > sure! > I think it is an odd product, trying to be a lot like Raspberry Pi in some > ways, and yet it has some strange design choices that make it more like a > vendor development board. > > A significant mistake, in my view, is that they did not expose the LVDS > signals for driving LCD panels efficiently, meaning that anyone wanting to > make a portable device with a screen apparently has to use "Raspberry Pi > level" solutions with SPI-based screens, despite the SoC really being > targeted > at the tablet market. > > But I guess one goal with the board was to familiarise developers with > PowerVR > on a relatively cheap platform, which is exactly what you are interested in. > :-) > >> Now I have to learn how to find and boot a prebuilt SD (only) image with >> Debian (so far I only found one that would reflash NAND). And then adapt >> makesd to be able to create LetuxOS images with Wheezy, Jessie, Stretch, >> Buster, LXDE, XfCE, Mate, QuantumSTEP, QtMoko, Replicant... And finally >> make SGX 1.14 work for them (I can already compile the pvrsrvkm driver for >> jz4780). > > With regard to making an image, the following page is informative: > > https://www.elinux.org/How_to_make_a_debian_rootfs_for_MIPS_CI20 > > However, I found it a lot easier to use multistrap to populate a root > filesystem, which is what I tend to use normally, anyway. I don't think > there's anything I can teach you about this. ;-) > > Again, this page helps with the bootable SD card: > > https://www.elinux.org/CI20_Dev_Zone#Making_a_bootable_SD_card_from_sources > > Anyway, it sounds like you are off to a good start! What I usually find the easiest approach is to find a simple .img which already includes the partitions, SPL+U-Boot, Kernel and some rootfs and expand it onto the SD card through dd... Then I can start tweaking it to prepare it for makesd. And then it is quite easy to work on improving/replacing the components for LetuxOS. If something breaks, there is always a working fallback which can be restored from the server. BR, Nikolaus _______________________________________________ Community mailing list [email protected] http://lists.goldelico.com/mailman/listinfo.cgi/community http://www.tinkerphones.org
