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Re: [PATCH v2] usb: Un-deprecate -usbdevice (except for -usbdevice audio
From: |
Samuel Thibault |
Subject: |
Re: [PATCH v2] usb: Un-deprecate -usbdevice (except for -usbdevice audio which gets removed) |
Date: |
Wed, 10 Mar 2021 16:02:09 +0100 |
User-agent: |
NeoMutt/20170609 (1.8.3) |
Markus Armbruster, le mer. 10 mars 2021 14:17:48 +0100, a ecrit:
> Thomas Huth <thuth@redhat.com> writes:
> > When trying to remove the -usbdevice option, there were complaints that
> > "-usbdevice braille" is still a very useful shortcut for some people.
>
> Pointer? I missed it.
For instance
https://lists.nongnu.org/archive/html/qemu-devel/2018-01/msg00693.html
> "braille" is the only driver with a factory. "-usbdevice braille" is
> sugar for
>
> -device usb-braille,chardev=braille -chardev braille,id=braille
> -machine usb=on
>
> It's buggy:
>
> $ qemu-system-x86_64 -S -usbdevice braille
> qemu-system-x86_64: -usbdevice braille: '-usbdevice' is deprecated,
> please use '-device usb-...' instead
> [three seconds tick by...]
> Segmentation fault (core dumped)
I don't have time to keep testing the usbdevice braille option of qemu
from git indeed.
But I do use the option at least weekly/monthly with releases. And some
braille users do depend on it for their daily work.
> It neglects to actually parse PARAMS:
>
> $ qemu-system-x86_64 -S -usbdevice braille:"I'm a Little Teapot"
> qemu-system-x86_64: -usbdevice braille:I'm a Little Teapot: '-usbdevice'
> is deprecated, please use '-device usb-...' instead
I wasn't aware of the issue, thus not fixed of course.
> The only one that has something approaching a leg to stand on is
> braille. Still, I fail to see why having to specify a backend is fine
> for any number of other devices, but not for braille.
Because people who use this option have no idea how they would be
supposed to make it work otherwise.
> -device usb-braille,chardev=braille -chardev braille,id=braille
> -machine usb=on
This is *way* beyond what people would work out, even if documented. For
them a braille device is just one device, there is no need for notion of
frontend/backend, this is all in just one "device" for them. Put another
way, it does not even make sense to build anything different from what
you wrote: using another chardev backend with usb-braille frontend
doesn't make sense, and exposing the braille chardev backend on another
usb frontend doesn't make sense either.
> If users need more time, we can extend the grace period.
They don't need time, they need things that are simple to use. That
three-option black magic really isn't.
Samuel