Re: [Qemu-devel] [PATCHv3] qxl: move to UNDEFINED on DESTROY_ALL_SURFACES{, _ASYNC}

[Alon Levy]

On Wed, Jun 29, 2011 at 05:00:20PM +0200, Gerd Hoffmann wrote:
> On 06/29/11 16:29, Alon Levy wrote:
> >On Wed, Jun 29, 2011 at 03:09:36PM +0200, Gerd Hoffmann wrote:
> >>Hi,
> >>
> >>>+    case QXL_IO_DESTROY_ALL_SURFACES_ASYNC: +        d->mode =
> >>>QXL_MODE_UNDEFINED;
> >>
> >>Should go to the async thread.
> >
> >doesn't it make more sense to do all state changes from the vcpu
> >thread? async thread can run much later, if you have a
> >QXL_IO_DESTROY_ALL_SURFACES_ASYNC followed by a
> >QXL_IO_CREATE_PRIMARY_ASYNC where the driver did not wait for the
> >completion of the ASYNC first, I would still like to support that,
> >but it won't work if I move this to the async thread.
> 
> I think we should disallow doing any I/O ops while one is in
> progress (except maybe QXL_IO_LOG).  Most I/O commands are I/O
> commands because they either needed for device setup or must be
> synchronous anyway.
> 
> QXL_IO_CREATE_PRIMARY_ASYNC wasn't exactly clever designed I think.
> Would have been better to enter native mode with another I/O
> command, then send the create request for the primary through the
> rings like all other surface commands.  But given it is a rare event
> it isn't that a big issue either.
> 

So - leave or change? I prefer to leave..
Maybe add a "pending async" flag to catch such occasions?

> cheers,
>   Gerd
> 
>