Xen internally registers a series of key handlers. When a key is
pressed,
the corresponding key handler is invoked, which ''printk'' (not
''printf''
to stdout)
internal statistical information, very useful for debugging.
When you are using a serial line, you directly enter this special mode,
i.e.
every key you press results in a key handler invoked (if exists).
When you are using the keyboard under Domain0, you need
XEN_ATTENTION_KEY
to use this function, (currently defined to Scroll Lk).
With PC keyboard (without Fn key), just simultaneously press Scroll Lk
+ key (such as ''p'', ''h'' etc)
However, with a laptop keyboard with Fn, it''s much much more tricky.
Typically, you need press Fn + Num Lk to ''produce'' Scroll Lk.
At this
point,
if you move on to press another key (say, press Fn, Num Lk,
''p'' all
together),
the key_handler is not invoked at all, and your keyboard hangs.
To restore your keyboard, release the previous three keys, and press Fn
+ Num Lk again.
The reason is: With Fn pressed, the scan code of the key (say
''p'') is
changed so that it''s not
recognized by Xen at all.
The solution is:
1. press Fn + Num Lk
2. release Fn but hold Num Lk
3. press another key (''p'', ''h'', etc)
Last but not least, as I said at the beginning, Xen internal statistical
information is output via ''printk''. If you are using a serial
line, you
could see the output immediately. But if you are under Domain0,
you won''t see anything: ''printk'' is not directed to
''stdout'' on Domain0.
Fortunately, you can use ''xi_read_console_ring'' to fetch the
''printk'' messages from Xen and print them to
''stdout'' on Domain0.
''xi_read_console_ring'' only exists in Xeno-unstable.bk tree.
FYI.
-- Bin
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On 17 Nov 2003, at 18:13, Bin Ren wrote:> Typically, you need press Fn + Num Lk to ''produce'' Scroll Lk. At this > point, > if you move on to press another key (say, press Fn, Num Lk, ''p'' all > together), > the key_handler is not invoked at all, and your keyboard hangs.This bug has now been fixed in both 1.1 and unstable tree. -- Bin ------------------------------------------------------- This SF. Net email is sponsored by: GoToMyPC GoToMyPC is the fast, easy and secure way to access your computer from any Web browser or wireless device. Click here to Try it Free! https://www.gotomypc.com/tr/OSDN/AW/Q4_2003/t/g22lp?Target=mm/g22lp.tmpl _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
> Xen internally registers a series of key handlers. When a key is > pressed, > the corresponding key handler is invoked, which ''printk'' (not ''printf'' > to stdout) > internal statistical information, very useful for debugging.I think the ''attention key'' is of dubious use, given that domain 0 takes over the VGA console as soon as it starts. Plus the current ''virtualisation'' of PS/2 access has never really worked 100% anyway. For start-of-day (bootstrap) debugging we have the serial line -- I think that everyone who''s doing the type of low-level hacking where those keys are useful has serial-line acces. For later debugging, I think we can just add a temporary DOM0_OP to execute a keyboard handler, and then use xi_read_console_ring to get the debug output. The eventual aim should be that most debug keys are only useful to low-level developers, and any others have some better defined access method (e.g., we need a better method for pulling performance counter values out of Xen). This then allows us to have the keyboard (and mouse) belonging solely to domain-0 after it has booted, as is already the case for the display device, which gets rid of the current flawed and pointless ''virtualisation'' of PS/2 access. -- Keir ------------------------------------------------------- This SF. Net email is sponsored by: GoToMyPC GoToMyPC is the fast, easy and secure way to access your computer from any Web browser or wireless device. Click here to Try it Free! https://www.gotomypc.com/tr/OSDN/AW/Q4_2003/t/g22lp?Target=mm/g22lp.tmpl _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel