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Re: [Qemu-arm] [Qemu-devel] [PATCH 3/3] hw/arm/virt-acpi-build: Add seco
From: |
Peter Maydell |
Subject: |
Re: [Qemu-arm] [Qemu-devel] [PATCH 3/3] hw/arm/virt-acpi-build: Add second UART to ACPI tables |
Date: |
Tue, 12 Dec 2017 12:47:06 +0000 |
On 12 December 2017 at 12:41, Laszlo Ersek <address@hidden> wrote:
> I agree. There's one user-visible complication: while with one UART,
> it's not possible to mix things up, with two UARTs, users will
> inevitably want to assign inverse roles to them, relative to what QEMU /
> the firmware assigns originally.
>
> E.g. if one PL011 is redirected to a regular file (debug messages) and
> the other one to stdio (console), there will be complaints that "I
> wanted it the other way around". The redirection happens on the backend
> (chardev) level, but the firmware won't see the difference on the
> frontend (PL011) level.
>
> Is it possible to add a new property to the UART nodes in the DTB, like
> "purpose"?
This is what the "chosen" stdout-path node in the DTB is for,
but you said you didn't want to look at that :-) (it means
"device to be used for boot console output".)
> Or can we make a virt-arm policy that "first -serial is always ...,
> second -serial is always ..."?
Well, the first -serial will always be the 0x09000000 one
that we have today, and the second -serial will be the other
one (unless you have -machine secure=yes, in which case
second -serial is the secure-only UART and third -serial is
the second NS UART).
Is this any different to the x86 case, where there are two
UARTs at different IO port/IRQ locations?
I think the only thing users really expect is that if you're
using just the one serial port for anything then it's the
first one.
thanks
-- PMM
- Re: [Qemu-arm] [Qemu-devel] [PATCH 2/3] hw/arm/virt: Add another UART to the virt board, (continued)
- [Qemu-arm] [PATCH 3/3] hw/arm/virt-acpi-build: Add second UART to ACPI tables, Peter Maydell, 2017/12/08
- Re: [Qemu-arm] [Qemu-devel] [PATCH 3/3] hw/arm/virt-acpi-build: Add second UART to ACPI tables, Shannon Zhao, 2017/12/12
- Re: [Qemu-arm] [Qemu-devel] [PATCH 3/3] hw/arm/virt-acpi-build: Add second UART to ACPI tables, Laszlo Ersek, 2017/12/12
- Re: [Qemu-arm] [Qemu-devel] [PATCH 3/3] hw/arm/virt-acpi-build: Add second UART to ACPI tables, Peter Maydell, 2017/12/12
- Re: [Qemu-arm] [Qemu-devel] [PATCH 3/3] hw/arm/virt-acpi-build: Add second UART to ACPI tables, Laszlo Ersek, 2017/12/12
- Re: [Qemu-arm] [Qemu-devel] [PATCH 3/3] hw/arm/virt-acpi-build: Add second UART to ACPI tables, Ard Biesheuvel, 2017/12/12
- Re: [Qemu-arm] [Qemu-devel] [PATCH 3/3] hw/arm/virt-acpi-build: Add second UART to ACPI tables, Laszlo Ersek, 2017/12/12
- Re: [Qemu-arm] [Qemu-devel] [PATCH 3/3] hw/arm/virt-acpi-build: Add second UART to ACPI tables, Peter Maydell, 2017/12/12
- Re: [Qemu-arm] [Qemu-devel] [PATCH 3/3] hw/arm/virt-acpi-build: Add second UART to ACPI tables, Laszlo Ersek, 2017/12/12
- Re: [Qemu-arm] [Qemu-devel] [PATCH 3/3] hw/arm/virt-acpi-build: Add second UART to ACPI tables,
Peter Maydell <=
- Re: [Qemu-arm] [Qemu-devel] [PATCH 3/3] hw/arm/virt-acpi-build: Add second UART to ACPI tables, Laszlo Ersek, 2017/12/12
- Re: [Qemu-arm] [Qemu-devel] [PATCH 3/3] hw/arm/virt-acpi-build: Add second UART to ACPI tables, Ard Biesheuvel, 2017/12/12
- Re: [Qemu-arm] [Qemu-devel] [PATCH 3/3] hw/arm/virt-acpi-build: Add second UART to ACPI tables, Peter Maydell, 2017/12/12
- Re: [Qemu-arm] [Qemu-devel] [PATCH 3/3] hw/arm/virt-acpi-build: Add second UART to ACPI tables, Ard Biesheuvel, 2017/12/12
- Re: [Qemu-arm] [Qemu-devel] [PATCH 3/3] hw/arm/virt-acpi-build: Add second UART to ACPI tables, Peter Maydell, 2017/12/12
- Re: [Qemu-arm] [Qemu-devel] [PATCH 3/3] hw/arm/virt-acpi-build: Add second UART to ACPI tables, Ard Biesheuvel, 2017/12/12
- Re: [Qemu-arm] [Qemu-devel] [PATCH 3/3] hw/arm/virt-acpi-build: Add second UART to ACPI tables, Peter Maydell, 2017/12/12
- Re: [Qemu-arm] [Qemu-devel] [PATCH 3/3] hw/arm/virt-acpi-build: Add second UART to ACPI tables, Ard Biesheuvel, 2017/12/12
- Re: [Qemu-arm] [Qemu-devel] [PATCH 3/3] hw/arm/virt-acpi-build: Add second UART to ACPI tables, Andrew Jones, 2017/12/12
- Re: [Qemu-arm] [Qemu-devel] [PATCH 3/3] hw/arm/virt-acpi-build: Add second UART to ACPI tables, Laszlo Ersek, 2017/12/12