From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Arnd Bergmann <arnd@kernel.org>,
"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 14:12:21 +0300 [thread overview]
Message-ID: <ZwkIFREb1Ia90hSR@smile.fi.intel.com> (raw)
In-Reply-To: <de65a5c8-1bbd-47b3-9dc5-de4ad93c41b8@app.fastmail.com>
On Fri, Oct 11, 2024 at 09:59:46AM +0000, Arnd Bergmann wrote:
> 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.
Do you have any examples of that in the kernel?
> 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.
Yes, but it's not what your code does.
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2024-10-11 11:12 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
2024-10-11 11:12 ` Andy Shevchenko [this message]
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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