On Mon, Apr 25, 2022 at 06:05:56PM +0100, Mark Cave-Ayland wrote:
On 25/04/2022 09:21, Martin Kletzander wrote:
> I wanted to deal with
https://bugzilla.redhat.com/2043498 and I got a
> suggesstion that removing deprecated features could actually make it
> easier to propagate the error. In the end (last patch) it turns out the
> error is still just reported with error_fatal, so it probably is not
> really needed, but I really wanted to dig into QEMU more and learn some
> of the internals for quite some time now. So I used the opportunity.
> The one-liner ended up being an 18 patch series which was, for someone
> who has just one commit in QEMU codebase, a pretty challenging task.
> Although I tried my best to do things properly, I am not sure whether I
> handled everything correctly, hence the RFC.
>
> Any comments are very much appreciated. Thanks and have a nice day ;)
>
> Martin Kletzander (18):
> hw/audio: Remove -soundhw support
> hw/input/tsc210x: Extract common init code into new function
> hw/audio: Simplify hda audio init
> hw/audio/lm4549: Add errp error reporting to init function
> tests/qtest: Specify audiodev= and -audiodev
> ui/vnc: Require audiodev=
> Introduce machine's default-audiodev property
> audio: Add easy dummy audio initialiser
> hw/display/xlnx_dp.c: Add audiodev property
> hw/input/tsc210x.c: Support machine-default audiodev with fallback
> hw/arm: Support machine-default audiodev with fallback
> hw/ppc: Support machine-default audiodev with fallback
> audio: Make AUD_register_card fallible and require audiodev=
> audio: Require AudioState in AUD_add_capture
> audio: Be more strict during audio backend initialisation
> audio: Remove legacy audio environment variables and options
> audio: Remove unused can_be_default
> audio/spiceaudio: Fail initialisation when not using spice
>
[...]
Thanks for the tidy-up! I'm not too familiar with the audio code, however one thing I
noticed is that in patch 11 you are using qdev_prop_set_string() to set the audiodev
for the machines.
For CharDevs there already exists a qdev_prop_set_chr() function which is used to
assign the chardev backend to the device, so I'm wondering if it makes sense to add a
similar qdev_prop_set_audiodev() function in the same way? Then if the method of
referencing the audiodev from the device ever changes from being a string containing
the name, it won't require updating all of the callers.
I guess that could be possible, but I'm not familiar with QEMU code much
and to be honest have no idea how I would go about doing that right now.
Finally a quick glance at the tsc210x and lm4549 devices indicates
that they are
using global device _init() functions which shouldn't really be used in modern
implementations. If you are interested in QOMify-ing these devices as part of this
work, then I can certainly help provide some pointers for getting started.
I thought about it for some devices. Not all the devices I touched
here, because I feel like that would lead to a rabbit hole. And 18
patches just because I wanted to error out in one condition was already
too much =) But I'll be glad for any pointers on where to start and how
should I get to it. Thanks.
ATB,
Mark.