From: "Philippe Mathieu-Daudé" <philmd@linaro.org>
To: "Peter Maydell" <peter.maydell@linaro.org>,
"Alex Bennée" <alex.bennee@linaro.org>
Cc: qemu-devel@nongnu.org, "Paolo Bonzini" <pbonzini@redhat.com>,
qemu-arm@nongnu.org,
"Evgeny Iakovlev" <eiakovlev@linux.microsoft.com>,
"Marc-André Lureau" <marcandre.lureau@redhat.com>
Subject: Re: [PATCH 09/12] hw/char/pl011: Check if transmitter is enabled
Date: Thu, 25 May 2023 15:17:47 +0200 [thread overview]
Message-ID: <af5d9e7a-a19c-b269-5a33-a3fc79e79094@linaro.org> (raw)
In-Reply-To: <CAFEAcA9EYLWnm6kEZGJn=Ah_wy1oE+8u0bZuVPq8=wTxtUo_Hw@mail.gmail.com>
On 25/5/23 14:55, Peter Maydell wrote:
> On Thu, 25 May 2023 at 13:52, Alex Bennée <alex.bennee@linaro.org> wrote:
>>
>>
>> Peter Maydell <peter.maydell@linaro.org> writes:
>>
>>> On Mon, 22 May 2023 at 16:32, Philippe Mathieu-Daudé <philmd@linaro.org> wrote:
>>>>
>>>> Do not transmit characters when UART or transmitter are disabled.
>>>>
>>>> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>>>
>>> Last time somebody tried to add checks on the tx/rx enable bits
>>> for the PL011 it broke 'make check' because the hand-rolled
>>> UART code in boot-serial-test and migration-test doesn't
>>> set up the UART control register strictly correctly:
>>>
>>> https://lore.kernel.org/qemu-devel/CAFEAcA8ZDmjP7G0eVpxcB1jiSGarZAbqPV0xr5WquR213mBUBg@mail.gmail.com/
Hmm I ran 'make check-qtest' my build directory only targets aarch64,
I probably missed the arm (32-bit) tests :/
>>> Given that imposing these checks doesn't help anything
>>> much and might break naive bare-metal tested-only-on-QEMU
>>> code, is it worthwhile ?
>>
>> Surely we aim to be a correct model so the fix should be in our naive
>> and incorrect code?
>
> In our own test suites, sure -- we should probably fix that
> even if we don't change the PL011 model to require it.
> But if we let this kind of thing get past us in our own testsuite,
> it suggests there's probably a lot of similar naive code out
> there in the world -- these Arm boards with PL011s are pretty
> commonly used for "my first bare metal assembly program" stuff
> and there's a lot of cargo-culting of how to do things like
> serial output, and programs that were never tested on any
> real hardware...
OK. I'll add a comment, keep the current behavior when TX is
disabled, but add a GUEST_ERROR log message.
next prev parent reply other threads:[~2023-05-25 13:18 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-22 15:31 [PATCH 00/12] hw/char/pl011: Implement TX (async) FIFO to avoid blocking the main loop Philippe Mathieu-Daudé
2023-05-22 15:31 ` [PATCH 01/12] util/fifo8: Fix typo in fifo8_push_all() description Philippe Mathieu-Daudé
2023-05-22 19:06 ` Francisco Iglesias
2023-05-23 13:22 ` Alex Bennée
2023-05-22 15:31 ` [PATCH 02/12] util/fifo8: Allow fifo8_pop_buf() to not populate popped length Philippe Mathieu-Daudé
2023-05-22 19:13 ` Francisco Iglesias
2023-05-23 13:25 ` Alex Bennée
2023-05-22 15:31 ` [PATCH 03/12] util/fifo8: Introduce fifo8_peek_buf() Philippe Mathieu-Daudé
2023-05-22 19:38 ` Francisco Iglesias
2023-05-23 13:25 ` Alex Bennée
2023-05-22 15:31 ` [PATCH 04/12] hw/char/pl011: Display register name in trace events Philippe Mathieu-Daudé
2023-05-23 13:31 ` Alex Bennée
2023-05-22 15:31 ` [PATCH 05/12] hw/char/pl011: Remove duplicated PL011_INT_[RT]X definitions Philippe Mathieu-Daudé
2023-05-23 13:32 ` Alex Bennée
2023-05-22 15:31 ` [PATCH 06/12] hw/char/pl011: Replace magic values by register field definitions Philippe Mathieu-Daudé
2023-05-23 13:34 ` Alex Bennée
2023-05-22 15:31 ` [PATCH 07/12] hw/char/pl011: Split RX/TX path of pl011_reset_fifo() Philippe Mathieu-Daudé
2023-05-23 13:35 ` Alex Bennée
2023-05-22 15:31 ` [PATCH 08/12] hw/char/pl011: Extract pl011_write_tx() from pl011_write() Philippe Mathieu-Daudé
2023-05-23 13:36 ` Alex Bennée
2023-05-22 15:31 ` [PATCH 09/12] hw/char/pl011: Check if transmitter is enabled Philippe Mathieu-Daudé
2023-05-23 13:36 ` Alex Bennée
2023-05-25 12:30 ` Peter Maydell
2023-05-25 12:51 ` Alex Bennée
2023-05-25 12:55 ` Peter Maydell
2023-05-25 13:17 ` Philippe Mathieu-Daudé [this message]
2023-05-22 15:31 ` [PATCH 10/12] hw/char/pl011: Check if receiver " Philippe Mathieu-Daudé
2023-05-23 13:38 ` Alex Bennée
2023-05-22 15:31 ` [PATCH 11/12] hw/char/pl011: Rename RX FIFO methods Philippe Mathieu-Daudé
2023-05-23 13:39 ` Alex Bennée
2023-05-22 15:31 ` [PATCH 12/12] hw/char/pl011: Implement TX FIFO Philippe Mathieu-Daudé
2023-05-23 13:47 ` Alex Bennée
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