> The idea is just to have one function. Whichever prints the
> string and panics the machine. If 'panic' does this properly
> (and properly meaning it actually prints data when using
> the earlyprintk=xen as well as console=hvc0) printout system
> the we cuold just use 'panic' and not worry about it.
>
>
> But if it does not, then we (and by we I mean you) should
> provide a variant of panic() that prints the data properly using the
> earlprintk mechanism. Preferrabily to make it generic.
I did a simple test, a serial cable was connected,  and console=hvc0 was 
added in grub.conf.
Whether earlyprintk=xen is set or not, both panic() and xen_raw_printk 
all can print out strings in gnttab_request_version of grant-table.c.

So I changed the

xen_raw_printk();
panic();

back to

panic();

Other change is the re-arrange "else if" format in 
gnttab_request_version function.

Please refer to the patch attached.

Thanks
Annie