From: Paolo Bonzini <pbonzini@redhat.com>
To: Peter Maydell <peter.maydell@linaro.org>,
QEMU Developers <qemu-devel@nongnu.org>
Cc: "Marc-André Lureau" <marcandre.lureau@redhat.com>
Subject: Re: [Qemu-devel] does a device model need to call qemu_chr_fe_accept_input() in its reset method?
Date: Thu, 3 May 2018 14:55:50 +0200 [thread overview]
Message-ID: <e77d927d-17fb-9543-adac-8281dd775f74@redhat.com> (raw)
In-Reply-To: <CAFEAcA87nQZLG493hSPb__zwKHVMsSNaS_qhY2EPghzTvJ9fwg@mail.gmail.com>
On 03/05/2018 14:49, Peter Maydell wrote:
> Hi; I noticed that one of our UART models, hw/char/cadence_uart.c,
> calls qemu_chr_fe_accept_input() in its reset method. This sort
> of makes sense, since device reset is a state transition from
> "I'm in a state where I've previously said I can't accept input"
> to "I'm in a state where I can accept input". However, it looks
> like none of the other UARTs do this.
>
> Is this a bug in our other UARTs, or does the chardev framework
> guarantee to forget about 'nope' responses from the fd_can_read
> callback on system reset?
No, system reset is not a particularly interesting event for most of the
backends.
So you have found a bug, and in fact it should be called on every rising
edge of can_read, so for example digic-uart.c is even more broken. I
vaguely remember looking at it years ago...
Paolo
prev parent reply other threads:[~2018-05-03 12:56 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-03 12:49 [Qemu-devel] does a device model need to call qemu_chr_fe_accept_input() in its reset method? Peter Maydell
2018-05-03 12:55 ` Paolo Bonzini [this message]
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