Re: Can't Mount CF-Card on boot of 2.6.15 Kernel on EPIA - VFS: Cannot open root device

From: Markus Biermaier
Date: Tue Jun 13 2006 - 17:09:06 EST



Am 12.06.2006 um 21:09 schrieb Jan Engelhardt:


Hm. Maybe http://lkml.org/lkml/2005/2/26/92 (updated version for
2.6.16/.17 below) can help you.

diff --fast -Ndpru linux-2.6.17-rc6~/block/genhd.c linux-2.6.17-rc6 +/block/genhd.c
--- linux-2.6.17-rc6~/block/genhd.c 2006-06-06 02:57:02.000000000 +0200
+++ linux-2.6.17-rc6+/block/genhd.c 2006-06-08 22:29:16.607058000 +0200
@@ -214,6 +214,52 @@ struct gendisk *get_gendisk(dev_t dev, i
return kobj ? to_disk(kobj) : NULL;
}

+/*
+ * printk a full list of all partitions - intended for
+ * places where the root filesystem can't be mounted and thus
+ * to give the victim some idea of what went wrong
+ */
+void printk_all_partitions(void)



Am 13.06.2006 um 09:47 schrieb Markus Biermaier:


to get the function "printk_all_partitions" compiled I simply commented out "mutex_lock" and "mutex_unlock"...

So the result before the boot-panic is:

...
here are the partitions available:
2100 500472 hde driver: ide-disk
2101 500440 hde1
...
What does this mean?


This holds the solution:
/* Note, unlike /proc/partitions I'm showing the numbers in hex
in the same format as the root= option */
printk("%02x%02x %10llu %s",
sgp->major, sgp->first_minor,
(unsigned long long)get_capacity(sgp) >> 1,
disk_name(sgp, 0, buf));

So my "/tftpboot/pxelinux.cfg/Cxxxxxx" is:
------------------------- [ BEGIN Cxxxxxx ] -------------------------
DEFAULT standard
LABEL standard
KERNEL vmlinuz
# APPEND initrd=initrd ramdisk_size=32768 root=/dev/hde1 udev acpi=off rootdelay=5
APPEND initrd=initrd ramdisk_size=32768 root=2101 udev acpi=off rootdelay=5
------------------------- [ END Cxxxxxx ] -------------------------

so the right root-string is: "root=2101".

But can anyone tell me how "root=/dev/hde1" translates to "root=2101"???

Thank you very much, Jan.

You brought me the solution.

Thanks
Markus

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