[PATCH 1/3] qi-update-README.patch
andy at openmoko.com
Sun Nov 23 21:44:31 CET 2008
Signed-off-by: Andy Green <andy at openmoko.com>
README | 46 ++++++++++++++++++++++++++++++----------------
1 files changed, 30 insertions(+), 16 deletions(-)
diff --git a/README b/README
index abff09f..f892773 100644
@@ -54,18 +54,30 @@ Booting Heuristics
Qi has one or more ways to fetch a kernel depending on the device it finds it is
running on, for example on GTA02 it can use NAND and SD card devices. It goes
through these device-specific storage devices in order and tries to boot the
-first viable kernel it finds, usually /boot/uImage.bin.
+first viable kernel it finds, usually /boot/uImage-device>.bin for example
-The kernel commandline used is associated with the storage device, this allows
-the correct root= line to be arrived at without any work. The inability to set
-the Qi kernel commandline externally is deliberate, two otherwise identical
-devices differing by the kernel commandline or other "environment" is not good.
-A whole class of bugs and support issues around private bootloader state are
+You can disable a rootfs for consideration for boot if you add a file
+/boot/noboot-<device>, eg, /boot/noboot-GTA02.
+The kernel commandline used is associated with the storage device and partition,
+this allows the correct root= line to be arrived at without any work.
If no kernel image can be found, Qi falls back to doing a memory test.
+Appending to commandline
+You can append to the Qi commandline by creating a file /boot/append-<device>,
+eg, /boot/append-GTA02 containing the additional kernel commandline you want.
+This means you can affect the boot per-rootfs, but that if you reimage the
+rootfs you at the same time define what is appeneded. Because these files are
+looked for with the <device> name in them, options can be selected depending on
+the device the rootfs is run on.
@@ -76,22 +88,24 @@ memory address in addition to kernel image. The ATAGs are issued accordingly.
Functional Differences from U-Boot on GTA02
- - Backlight is not enabled until Linux starts after a few seconds
+ - Backlight and USB is not enabled until Linux starts after a few seconds
+ - No startup splash screen
- - kernel loglevel is set to NOT output gobs of text to the screen
+ - by default there is no boot spew on the LCM
- - On GTA02 will ALWAYS boot from uSD if first partition is ext2 and contains
- /boot/uImage.bin, otherwise boots from NAND
+ - On GTAxx boots from first uSD ext2 / 3 partition containing
+ /boot/uImage-<devicename>.bin present, eg, /boot/uImage-GTA02.bin, it checks
+ first three partitions in turn
- - On GTA03 will ALWAYS boot from uSD second partition if /boot/uImage.bin is
- present otherwise try the third / backup partition
+ - On GTA01 and 02 if nothing is workable on the SD Card, or it is not present,
+ Qi will try to boot from NAND
- - No startup splash screen
+ - You can disable a partition for boot by creating /boot/noboot-<devicename>,
+ eg, /boot/noboot-GTA02, it will skip it and check the next partition
- Way faster
- There is no concept of "staying in the bootloader". The bootloader exits to
Linux as fast as possible, that's all it does.
- - USB is not started until Linux starts around 5 seconds after boot, there is
- no DFU.
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