# Configs we already tried ## Surface RT 1 ### @Leander's trial and fail *Note to members of the gitbook: I don't know if it is useful to make this person-specific.* #### #001 This hangs at without supplying device tree with dtb=\ If device tree is supplied, cpuidle complains at printed.\ `[ 0.000000] platform regulatory.0: Direct firmware load for regulatory.db failed with error -2` \ `[ 0.000000] cfg80211: failed to load regulatory.db` {% file src="" %} \#001 .config {% endfile %} {% file src="" %} \#001 device tree {% endfile %} {% hint style="info" %} Testing without device tree from here on {% endhint %} #### #002 Changed:`CONFIG_CFG80211=n` \ `[ 0.000000] platform regulatory.0: Direct firmware load for regulatory.db failed with error -2` \ `[ 0.000000] cfg80211: failed to load regulatory.db`\ This is issue doesn't exist anymore, it just freezes at `[ 0.000000] Freeing unused kernel memory: 1024K` Note the line, clock should be 100kHz`[ 0.000000] sched_clock: 32 bits at 100 Hz, resolution 10000000ns, wraps every 21474836475000000ns` `[ 0.000000] Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled` \ `[ 0.000000] Warning: unable to open an initial console.`\ It looks like it's using some serial and then is unable to open a console. -> No device tree so it doesn't know /dev/ttyS0 (UART-A) {% file src="" %} \#002 .config {% endfile %} {% file src="" %} \#002 log {% endfile %} #### #003 `CONFIG_FB_EFI=y`\ `CONFIG_CMDLINE="console=ttyS0,115200 console=tty0 earlyprintk initcall_debug sched_debug lpj=10000"` It booted, then disabled uart and printed to the screen. Log only contains print from uart. Stuck at the same line. {% file src="" %} \#003 .config {% endfile %} {% file src="" %} \#003 log {% endfile %} #### #004 `CONFIG_CMDLINE="console=ttyS0,115200 console=tty0 earlycon earlyprintk initcall_debug sched_debug lpj=10000"` Log should be the same apart from the cmdline. Again, it displayed to display, so log doesn't include that output. {% file src="" %} \#004 .config {% endfile %} {% file src="" %} \#004 log {% endfile %} #### #005 `CONFIG_CMDLINE="console=ttyS0,115200 earlycon earlyprintk initcall_debug sched_debug lpj=10000"` Screen with a cursor, all output on uart. But because there is no device tree, no console from initrd. {% file src="" %} \#005 .config {% endfile %} {% file src="" %} \#005 log {% endfile %} {% hint style="info" %} Testing with device tree from here on {% endhint %} #### #006 Nothing changed in config. Only added device tree. Kernel panic: `[ 0.000000] Unable to handle kernel NULL pointer dereference at virtual address 00000010`Has to do with cpuidle. You can also see complaints about a bad device tree. {% file src="" %} \#006 .config {% endfile %} {% file src="" %} \#006 log {% endfile %} {% file src="" %} \#006 device tree {% endfile %} #### #007 Only device tree edits. Screen has no cursor anymore, only backlight is turned on. You can't print something on it with `echo hello >> /dev/fb0` or `echo hello >> /dev/tty0` Successful boot to Buildroot. Note: Log has a lot of entries two times. {% file src="" %} \#007 .config {% endfile %} {% file src="" %} \#007 log {% endfile %} {% file src="" %} \#007 device tree {% endfile %} #### #008 `CONFIG_VGA_ARB=n`\ `CONFIG_TEGRA_HOST1X=n`\ `CONFIG_DRM=n` No different screen behaviour. Log has some commands at the bottom. {% file src="" %} \#008 .config {% endfile %} {% file src="" %} \#008 log {% endfile %} {% file src="" %} \#008 device tree {% endfile %} #### #009 No config changed. Only device tree edits. Added nodes to it until dtc didn't complain about anything. Some strange screen behaviour. `[ 0.000000] tegra20-cpufreq tegra20-cpufreq: operating points not found` \ `[ 0.000000] tegra20-cpufreq tegra20-cpufreq: please update your device tree` Looks like some cpu frequency nodes have to be added to device tree. {% file src="" %} \#009 .config {% endfile %} {% file src="" %} \#009 log {% endfile %} {% file src="" %} \#009 device tree {% endfile %} #### #010 Only device tree edits. Screen still doesn't work. Boots fine to Buildroot. Log has commands at the bottom. {% file src="" %} \#010 .config {% endfile %} {% file src="" %} \#010 log {% endfile %} {% file src="" %} \#010 device tree {% endfile %} #### #011 `CONFIG_CMDLINE="console=ttyS0,115200 console=tty0 earlyprintk initcall_debug sched_debug lpj=10000"` Found out that screen works, but it gets cleared when Busybox (from ramdisk) starts. At least I think at that point it gets cleared, not 100% sure. {% file src="" %} \#011 .config {% endfile %} {% file src="" %} \#011 log {% endfile %} {% file src="" %} \#011 device tree {% endfile %} #### #012 `CONFIG_CMDLINE="console=ttyS0,115200 earlyprintk initcall_debug sched_debug lpj=10000"` Minimal device tree with sd-card+emmc+uart, it includes tegra30.dtsi No display output with this command line, but you get log output when adding `console=tty0`, but afterwards it stops around when Busybox takes over. {% file src="" %} \#012 .config {% endfile %} {% file src="" %} \#012 log {% endfile %} {% file src="" %} \#012 device tree {% endfile %} #### #013 Added a raspberry pi rootfs. Specifying root= option with efi shell Display stops working after the line `[ 251.431349] tegra-devfreq 6000c800.actmon: Failed to get emc clock` Log contains output from rootfs. {% file src="" %} \#013 .config {% endfile %} {% file src="" %} \#013 log {% endfile %} {% file src="" %} \#013 device tree {% endfile %} {% hint style="info" %} Config reseted. Started from a new one. {% endhint %} #### #014 `CONFIG_EFI_STUB=y` \ `CONFIG_EFI=y`\ `CONFIG_CMDLINE="console=ttyS0,115200n8 earlyprintk initcall_debug sched_debug lpj=10000 boot_delay=50"`\ `CONFIG_CMDLINE_EXTEND=y`\ `CONFIG_SMP=n`\ `CONFIG_CACHE_L2X0=n`\ `CONFIG_EARLY_PRINTK=y`\ `CONFIG_DEBUG_TEGRA_UART=y`\ `CONFIG_TEGRA_DEBUG_UARTA=y`\ `CONFIG_BOOT_PRINTK_DELAY=y` `CONFIG_BOOT_PRINTK_DELAY=y` and `boot_delay=50(cmdline)` are necessary so mmc driver gets loaded early enough. Log contains a few commands from rootfs. {% file src="" %} \#014 .config {% endfile %} {% file src="" %} \#014 log {% endfile %} {% file src="" %} \#014 device tree {% endfile %} #### #015 I'm not sure what changed. Working display with booted raspberry pi os! ![](https://2395005476-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MJQb34R_xPz0ll0scbM%2F-MT0Kdl31nmBu746PDCW%2F-MT0ZgF041J6PkY6Lygp%2FIMG_20210208_131108.jpg?alt=media\&token=ca125967-bbbb-4b8f-b8da-a90f327a3108) {% file src="" %} \#015 .config {% endfile %} {% file src="" %} \#015 log {% endfile %} {% file src="" %} \#015 device tree {% endfile %} ## Surface RT 2