Re: [Qemu-devel] [PATCH 00/23] Suppress unused default drives

[Markus Armbruster]

Paul Brook <address@hidden> writes:

>> > *can* use it for something entirely else, if=sd notwithstanding:
>> >     (qemu) device_add lsi
>> >     (qemu) device_add scsi-cd,drive=sd0
>> 
>> If/when we get a PCI SD card controller model, would all the PCI
>> using machines need to be added to take the 'no default sd card'
>> setting out again, or does it get overridden anyway if you say
>> "and I'd like an sd controller"?
>
> For SD cards we shouldn't need this to start with.  Why are we creating SD 
> cards when there's no host controller to connect them to?  Surely we shold be 
> able to figure that out automatically.  Especially important for board 
> variants with multiple SD interfaces.
>
> Is this all a hangover from before we have proper -drive options?

As far as I can tell, we used to create default drives unconditionally.
Commit aa40fc9c (v0.13) added -nodefaults to suppress them all, and
commit ac33f8fa (v0.13) added means for boards to suppress them
selectively.

Commit e3260506 (v1.1) suppressed SD card for xilinx-zynq-a9, and commit
ad0bbc56 (v1.1) suppress all three for s390-virtio.

My patch series fixes up all boards to suppress all unused drives.
Better late than never.

We can certainly try to detect "board uses default drive X"
automatically, so that boards don't have to declare their need
explicitly.  But considering how close we are to the freeze, I prefer my
simple and safe fix for now.  We can always improve on it later.