Re: [Qemu-devel] [PATCH v2 4/5] console: pass Monitor to vga_hw_screen_dump/hw_vga_dump

[Alon Levy <alevy@redhat.com>]

On Tue, Mar 13, 2012 at 10:35:55AM -0300, Luiz Capitulino wrote:
> On Sun, 11 Mar 2012 21:26:43 +0200
> Alon Levy <alevy@redhat.com> wrote:
> 
> > Passes the Monitor ptr to the screendump implementation to all for
> > monitor suspend and resume for qxl to fix screendump regression.
> > 
> > graphics_console_init signature change required touching every
> > implemented of screen_dump. There is no change other then an added
> > parameter. qxl will make use of it in the next patch.
> 
> NACK on this one.
> 
> The Monitor object should be restricted to HMP. This patch spreads it to
> what's going to be the QMP implementation of screendump.
> 
> The first step here should be to convert the screendump command to the qapi,
> and lock the HMP shell in hmp_screendump().
> 
> However, this brings a new interesting problem: the HMP implementation is
> actually a QMP client, meaning that it won't have a way to figure out
> screendump completion either :)
> 
> Some solutions that come to my mind:
> 
>  1. Pool the screendump file creation from a timer.
> 
>     Cons: it may return before the file is fully written to disk
> 

We know what the file size should be, so we can poll for the actual
size. Actually why do we need to poll? we could add a
"internal.screendump.complete" or "internal-query-screendump", no?

>  2. Use inotify
> 
>     Cons: what about windows?
> 
>  3. Introduce query-screendump that returns the last screendump status
> 
>     Cons: this is actually making screendump async
> 
> 
> Anthony, do you have any ideas?
> 
> Btw, I've started doing the screendump conversion to the qapi, I'll post it
> soon.

I've already sent patches once for a new qapi command, I don't mind you
doing this of course.