From: "Arnd Bergmann" <arnd@arndb.de>
To: "Richard Cochran" <richardcochran@gmail.com>,
"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>
Cc: "Arnd Bergmann" <arnd@kernel.org>,
"Thomas Weißschuh" <thomas.weissschuh@linutronix.de>,
"Andrew Lunn" <andrew+netdev@lunn.ch>,
"David S . Miller" <davem@davemloft.net>,
"Eric Dumazet" <edumazet@google.com>,
"Jakub Kicinski" <kuba@kernel.org>,
"Paolo Abeni" <pabeni@redhat.com>,
"Tianfei Zhang" <tianfei.zhang@intel.com>,
"Jonathan Lemon" <jonathan.lemon@gmail.com>,
"Vadim Fedorenko" <vadim.fedorenko@linux.dev>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Thomas Weißschuh" <linux@weissschuh.net>,
"Calvin Owens" <calvin@wbinvd.org>,
"Philipp Stanner" <pstanner@redhat.com>,
Netdev <netdev@vger.kernel.org>,
linux-kernel@vger.kernel.org, linux-fpga@vger.kernel.org
Subject: Re: [PATCH] RFC: ptp: add comment about register access race
Date: Tue, 04 Mar 2025 09:24:35 +0100 [thread overview]
Message-ID: <7fd3c712-4c31-435c-80c1-1e042c9b5999@app.fastmail.com> (raw)
In-Reply-To: <Z8Z87mkuRqE6VOTy@hoboy.vegasvil.org>
On Tue, Mar 4, 2025, at 05:09, Richard Cochran wrote:
> On Mon, Mar 03, 2025 at 09:50:01AM +0200, Andy Shevchenko wrote:
>> Perhaps it's still good to have a comment, but rephrase it that the code is
>> questionable depending on the HW behaviour that needs to be checked.
>
> IIRC both ixp4xx and the PCH are the same design and latch high reg on
> read of low.
Ok, if that's a common thing, let's assume that the drivers are
all correct for the respective hardware and discard my patch.
With the patch I have queued up in the asm-generic tree, the
behavior changes so ioread64_lo_hi() no longer gets turned
into a single 64-bit access, and that is then more likely to
be correct for both 32-bit and 64-bit architectures in case the
device doesn't actually implement 64-bit transactions but does
correctly latch the contents.
Arnd
prev parent reply other threads:[~2025-03-04 8:24 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-27 14:17 [PATCH] RFC: ptp: add comment about register access race Arnd Bergmann
2025-02-27 15:23 ` Andy Shevchenko
2025-03-02 20:55 ` Richard Cochran
2025-03-03 7:50 ` Andy Shevchenko
2025-03-04 4:09 ` Richard Cochran
2025-03-04 8:24 ` Arnd Bergmann [this message]
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