Re: [PATCH] hw/char/pl011: fix receiving multiple chars

From: Peter Maydell <peter.maydell@linaro.org>
To: Zack Marvel <zpmarvel@gmail.com>
Cc: QEMU Trivial <qemu-trivial@nongnu.org>,
	qemu-arm <qemu-arm@nongnu.org>,
	QEMU Developers <qemu-devel@nongnu.org>
Subject: Re: [PATCH] hw/char/pl011: fix receiving multiple chars
Date: Sun, 21 Feb 2021 15:19:33 +0000	[thread overview]
Message-ID: <CAFEAcA8BB=ka9nPv9-okHhHwXOAbfbaXs9OFn4bNkbU+b-H+FQ@mail.gmail.com> (raw)
In-Reply-To: <20210221150430.6223-1-zpmarvel@gmail.com>

On Sun, 21 Feb 2021 at 15:04, Zack Marvel <zpmarvel@gmail.com> wrote:
>
> When using the GTK UI with libvte, multicharacter keystrokes are not
> sent correctly (such as arrow keys). This is not an issue for e.g. the
> SDL UI because qemu_chr_be_write is called with len=1 for each character
> (SDL sends more than once keystroke).
>
> Buglink: https://bugs.launchpad.net/qemu/+bug/1407808
>
> Signed-off-by: Zack Marvel <zpmarvel@gmail.com>

> @@ -300,7 +300,9 @@ static void pl011_put_fifo(void *opaque, uint32_t value)
>
>  static void pl011_receive(void *opaque, const uint8_t *buf, int size)
>  {
> -    pl011_put_fifo(opaque, *buf);
> +    for (int i = 0; i < size; i++) {
> +        pl011_put_fifo(opaque, buf[i]);
> +    }
>  }

I think this is a bug in whatever is on the other end
of the chardev connection. The pl011 can_receive routine
only ever returns 0 or 1, so it is an error for the
code calling its receive function to ever pass a
size that is greater than 1.

thanks
-- PMM