Re: Xen on Arndale with SSD

[Julien Grall <julien.grall@linaro.org>]

On 04/19/2013 10:11 AM, Sander Bogaert wrote:

> Hi,
> 
> I was wondering if anyone managed to use an ssd in this setup yet? I
> gave it a try:
> 
> - Julien's xen / dom0 / domU branches
> - Comay Venus 3S SSD drive
> - Changed the dts compiled in Xen to have root=/dev/sda1 for dom0
> kernel parameter.
> - The bootloader is on the SD card, the kernel and xen are loaded
> using PXE, the dom0 rootfs is on the ssd disk.
> 
> Xen hangs on (complete log attached):
> (XEN) 3... 2... 1...
> (XEN) *** Serial input -> DOM0 (type 'CTRL-a' three times to switch
> input to Xen)
> (XEN) Freed 204kB init memory.


I think linux hangs before hvc console is initialized. Could you try
to apply this hackish patch and resent the log? This patch will directly
call the console hypercall instead of buffering messages.

diff --git a/kernel/printk.c b/kernel/printk.c
index abbdd9e..6975215 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -1652,6 +1652,8 @@ asmlinkage int printk_emit(int facility, int level,
 }
 EXPORT_SYMBOL(printk_emit);

+void xen_raw_console_write(const char *buf);
+
 /**
  * printk - print a kernel message
  * @fmt: format string
@@ -1677,6 +1679,7 @@ asmlinkage int printk(const char *fmt, ...)
 {
        va_list args;
        int r;
+       static char buf[512];

 #ifdef CONFIG_KGDB_KDB
        if (unlikely(kdb_trap_printk)) {
@@ -1687,9 +1690,12 @@ asmlinkage int printk(const char *fmt, ...)
        }
 #endif
        va_start(args, fmt);
-       r = vprintk_emit(0, -1, NULL, 0, fmt, args);
+//     r = vprintk_emit(0, -1, NULL, 0, fmt, args);
+       r = vsnprintf(buf, sizeof(buf), fmt, args);
        va_end(args);

+       xen_raw_console_write(buf);
+
        return r;
 }
 EXPORT_SYMBOL(printk);