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Re: [PATCH] hw/char/pl011: Output characters using best-effort mode
From: |
Peter Maydell |
Subject: |
Re: [PATCH] hw/char/pl011: Output characters using best-effort mode |
Date: |
Fri, 21 Feb 2020 12:44:29 +0000 |
On Fri, 21 Feb 2020 at 11:44, Paolo Bonzini <address@hidden> wrote:
>
> On 21/02/20 11:21, Peter Maydell wrote:
> > Before you do that, I would suggest investigating:
> > * is this a problem we've already had on x86 and that there is a
> > standard solution for
> Disconnected sockets always lose data (see tcp_chr_write in
> chardev/char-socket.c).
>
> For connected sockets, 8250 does at most 4 retries (each retry is
> triggered by POLLOUT|POLLHUP). After these four retries the output
> chardev is considered broken, just like in Gavin's patch, and only a
> reset will restart the output.
>
> > * should this be applicable to more than just the socket chardev?
> > What's special about the socket chardev?
>
> For 8250 there's no difference between socket and everything else.
Interesting, I didn't know our 8250 emulation had this
retry-and-drop-data logic. Is it feasible to put it into
the chardev layer instead, so that every serial device
can get it without having to manually implement it?
thanks
-- PMM
- [PATCH] hw/char/pl011: Output characters using best-effort mode, Gavin Shan, 2020/02/20
- Re: [PATCH] hw/char/pl011: Output characters using best-effort mode, Philippe Mathieu-Daudé, 2020/02/20
- Re: [PATCH] hw/char/pl011: Output characters using best-effort mode, Marc Zyngier, 2020/02/20
- Re: [PATCH] hw/char/pl011: Output characters using best-effort mode, Peter Maydell, 2020/02/20
- Re: [PATCH] hw/char/pl011: Output characters using best-effort mode, Peter Maydell, 2020/02/21
- Re: [PATCH] hw/char/pl011: Output characters using best-effort mode, Paolo Bonzini, 2020/02/21
- Re: [PATCH] hw/char/pl011: Output characters using best-effort mode,
Peter Maydell <=
- Re: [PATCH] hw/char/pl011: Output characters using best-effort mode, Paolo Bonzini, 2020/02/21
- Re: [PATCH] hw/char/pl011: Output characters using best-effort mode, Peter Maydell, 2020/02/21
- Re: [PATCH] hw/char/pl011: Output characters using best-effort mode, Paolo Bonzini, 2020/02/21
- Re: [PATCH] hw/char/pl011: Output characters using best-effort mode, Gavin Shan, 2020/02/23
- Re: [PATCH] hw/char/pl011: Output characters using best-effort mode, Gavin Shan, 2020/02/23