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From: "Arnd Bergmann" <arnd@arndb.de>
To: "Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
	"Arnd Bergmann" <arnd@kernel.org>
Cc: "Rafael J . Wysocki" <rafael@kernel.org>,
	"Len Brown" <lenb@kernel.org>,
	"Mario Limonciello" <mario.limonciello@amd.com>,
	"Jarred White" <jarredwhite@linux.microsoft.com>,
	"Perry Yuan" <perry.yuan@amd.com>,
	"Easwar Hariharan" <eahariha@linux.microsoft.com>,
	linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/3] acpi: allow building without CONFIG_HAS_IOPORT
Date: Fri, 11 Oct 2024 09:59:46 +0000	[thread overview]
Message-ID: <de65a5c8-1bbd-47b3-9dc5-de4ad93c41b8@app.fastmail.com> (raw)
In-Reply-To: <Zwj1p3uMEA24a0sU@smile.fi.intel.com>

On Fri, Oct 11, 2024, at 09:53, Andy Shevchenko wrote:
> On Fri, Oct 11, 2024 at 06:18:18AM +0000, Arnd Bergmann wrote:
>
> ...
>
>> +	if (!IS_ENABLED(CONFIG_HAS_IOPORT)) {
>> +		*value = BIT_MASK(width);
>> +		return AE_NOT_IMPLEMENTED;
>
> Perhaps it has already been discussed, but why do we need to file value with
> semi-garbage when we know it's invalid anyway?

It's not strictly necessary, just precaution for possible callers
that use the resulting data without checking the error code.

The all-ones data is what an x86 PC would see when an I/O
port is read that is not connected to any device.

     Arnd

  reply	other threads:[~2024-10-11 10:00 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-11  6:18 [PATCH v2 1/3] acpi: make EC support compile-time conditional Arnd Bergmann
2024-10-11  6:18 ` [PATCH v2 2/3] acpi: allow building without CONFIG_HAS_IOPORT Arnd Bergmann
2024-10-11  9:53   ` Andy Shevchenko
2024-10-11  9:59     ` Arnd Bergmann [this message]
2024-10-11 11:12       ` Andy Shevchenko
2024-10-11 11:28         ` Rafael J. Wysocki
2024-10-11 13:39           ` Andy Shevchenko
2024-10-11 11:40         ` Arnd Bergmann
2024-10-11 13:41           ` Andy Shevchenko
2024-10-11  6:18 ` [PATCH v2 3/3] acpi: processor_perflib: extend X86 dependency Arnd Bergmann
2024-10-12 22:38   ` kernel test robot
2024-10-11 16:56 ` [PATCH v2 1/3] acpi: make EC support compile-time conditional Guenter Roeck
2024-10-12 10:18 ` Hans de Goede
2024-10-21 11:39 ` Rafael J. Wysocki
2024-10-24 15:49   ` Rafael J. Wysocki
2024-10-30 12:40     ` Arnd Bergmann

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