[Qemu-devel] qemu vl.c hw/omap.c

[Qemu-devel] qemu vl.c hw/omap.c

[Andrzej Zaborowski]

CVSROOT:	/sources/qemu
Module name:	qemu
Changes by:	Andrzej Zaborowski <balrog>	07/12/04 00:10:35

Modified files:
	.              : vl.c 
	hw             : omap.c 

Log message:
	Always create an SD bdrv, so that PXA and OMAP boards can boot with
	no card inserted again.  Eventually SD, CDROM and floppy should all
	be registered conditionally depending on machine.

CVSWeb URLs:
http://cvs.savannah.gnu.org/viewcvs/qemu/vl.c?cvsroot=qemu&r1=1.375&r2=1.376
http://cvs.savannah.gnu.org/viewcvs/qemu/hw/omap.c?cvsroot=qemu&r1=1.27&r2=1.28

Re: [Qemu-devel] qemu vl.c hw/omap.c

[Paul Brook]

> Log message:
> 	Always create an SD bdrv, so that PXA and OMAP boards can boot with
> 	no card inserted again.  Eventually SD, CDROM and floppy should all
> 	be registered conditionally depending on machine.

This seems the wrong way to solve this problem. The SD emulation should be 
able to cope with no device being present.

The general case should be a hotplugable interface, with cold-plug interfaces 
(e.g. IDE harddrives) being the exception.

Paul

Re: [Qemu-devel] qemu vl.c hw/omap.c

[andrzej zaborowski]

On 04/12/2007, Paul Brook <paul@codesourcery.com> wrote:
> > Log message:
> >       Always create an SD bdrv, so that PXA and OMAP boards can boot with
> >       no card inserted again.  Eventually SD, CDROM and floppy should all
> >       be registered conditionally depending on machine.
>
> This seems the wrong way to solve this problem. The SD emulation should be
> able to cope with no device being present.

The bdrv's represent the concept of "drive" rather than "media", and
also in the case the bdrv must be present whenever there is a SD slot,
not an SD card (so that monitor command change and eject can be used).
I agree that not all machines have an SD slot, as not all machines
have a cd-rom drive or floppy drive.

So this needs to be fixed but this commit was a quick fix for the
regression from the -drive patch.
Regards

Re: [Qemu-devel] qemu vl.c hw/omap.c

[Paul Brook]

On Tuesday 04 December 2007, andrzej zaborowski wrote:
> On 04/12/2007, Paul Brook <paul@codesourcery.com> wrote:
> > > Log message:
> > >       Always create an SD bdrv, so that PXA and OMAP boards can boot
> > > with no card inserted again.  Eventually SD, CDROM and floppy should
> > > all be registered conditionally depending on machine.
> >
> > This seems the wrong way to solve this problem. The SD emulation should
> > be able to cope with no device being present.
>
> The bdrv's represent the concept of "drive" rather than "media", and
> also in the case the bdrv must be present whenever there is a SD slot,
> not an SD card (so that monitor command change and eject can be used).
> I agree that not all machines have an SD slot, as not all machines
> have a cd-rom drive or floppy drive.

Right, but I think you're going in the wrong direction. Most scsi interfaces 
do support hotplug of devices. For USB mass storage the whole controller is 
hotplug. Pre-allocating all possible devices simply doesn't scale.

Paul

Re: [Qemu-devel] qemu vl.c hw/omap.c

[andrzej zaborowski]

On 04/12/2007, Paul Brook <paul@codesourcery.com> wrote:
> On Tuesday 04 December 2007, andrzej zaborowski wrote:
> > On 04/12/2007, Paul Brook <paul@codesourcery.com> wrote:
> > > > Log message:
> > > >       Always create an SD bdrv, so that PXA and OMAP boards can boot
> > > > with no card inserted again.  Eventually SD, CDROM and floppy should
> > > > all be registered conditionally depending on machine.
> > >
> > > This seems the wrong way to solve this problem. The SD emulation should
> > > be able to cope with no device being present.
> >
> > The bdrv's represent the concept of "drive" rather than "media", and
> > also in the case the bdrv must be present whenever there is a SD slot,
> > not an SD card (so that monitor command change and eject can be used).
> > I agree that not all machines have an SD slot, as not all machines
> > have a cd-rom drive or floppy drive.
>
> Right, but I think you're going in the wrong direction. Most scsi interfaces
> do support hotplug of devices. For USB mass storage the whole controller is
> hotplug. Pre-allocating all possible devices simply doesn't scale.

We don't pre-allocate all possible devices, only the "drives" which
are integral part of the machine (as is the case of the SD slot in a
Zaurus, soldered to the PCB). New bdrv's can still be added and
removed in runtime for hotplugged devices and I have no intetion to
change that.

If you want to use the hotplugging-like mechanism for inserting
removable media like SD, CD or floppy, that would mean scrapping the
whole bdrv_is_removable(), bdrv_is_inserted(), bdrv_media_changed()
api.
Regards

Re: [Qemu-devel] qemu vl.c hw/omap.c

[Laurent Vivier]

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Le mardi 04 décembre 2007 à 01:20 +0000, Paul Brook a écrit :
> On Tuesday 04 December 2007, andrzej zaborowski wrote:
> > On 04/12/2007, Paul Brook <paul@codesourcery.com> wrote:
> > > > Log message:
> > > >       Always create an SD bdrv, so that PXA and OMAP boards can boot
> > > > with no card inserted again.  Eventually SD, CDROM and floppy should
> > > > all be registered conditionally depending on machine.
> > >
> > > This seems the wrong way to solve this problem. The SD emulation should
> > > be able to cope with no device being present.
> >
> > The bdrv's represent the concept of "drive" rather than "media", and
> > also in the case the bdrv must be present whenever there is a SD slot,
> > not an SD card (so that monitor command change and eject can be used).
> > I agree that not all machines have an SD slot, as not all machines
> > have a cd-rom drive or floppy drive.
> 
> Right, but I think you're going in the wrong direction. Most scsi interfaces 
> do support hotplug of devices. For USB mass storage the whole controller is 
> hotplug. Pre-allocating all possible devices simply doesn't scale.

Hi Paul,

I think Andrzez is doing it correctly.

He only adds an entry in drives_table[] without creating any bdrv
(because he doesn't provide file).
Then in omap.c, he creates the device, not the media. And as Palm
Tunsgten is the only machine calling omap310_mpu_init(), the device is
only created for it. And then he will be able to introduce card (file)
in the SD reader.

Laurent
-- 
------------- Laurent.Vivier@bull.net  --------------
       "Any sufficiently advanced technology is
  indistinguishable from magic." - Arthur C. Clarke

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