From: Adrian Hunter <adrian.hunter@intel.com>
To: Frank Li <Frank.li@oss.nxp.com>, Sam Agazaryan <samagazaryan@google.com>
Cc: <linux-i3c@lists.infradead.org>,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
Frank Li <Frank.Li@nxp.com>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
Wolfram Sang <wsa+renesas@sang-engineering.com>,
Arnd Bergmann <arnd@arndb.de>,
"Meagan Lloyd" <meaganlloyd@linux.microsoft.com>,
Vitor Soares <vitor.soares@toradex.com>,
Oleksandr Shulzhenko <oleksandr.shulzhenko.viktorovych@intel.com>,
Boris Brezillon <boris.brezillon@collabora.com>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v5 3/5] i3c: use actual_len for read transfers
Date: Mon, 28 Sep 2026 13:42:56 +0300 [thread overview]
Message-ID: <22623823-a2c7-4627-b123-12d1baed0e93@intel.com> (raw)
In-Reply-To: <araSUuwTSx0aIuDp@lizhi-Precision-Tower-5810>
On 25/09/2026 18:25, Frank Li wrote:
> On Mon, Sep 21, 2026 at 11:06:01PM +0000, Sam Agazaryan wrote:
>> Currently only the amd and svc I3C controller drivers populate
>> i3c_xfer.actual_len on reads, while dw-i3c-master and mipi-i3c-hci
>> overwrite i3c_xfer.len with the received byte count and leave actual_len
>> as 0. Because of this inconsistency, mctp-i3c reads xfer.len instead of
>> xfer.actual_len, making it fail on controllers that do not mutate len.
>>
>> Unify read length reporting across the subsystem:
>> - Clarify in <linux/i3c/device.h> that actual_len reflects the actual
>> number of bytes transferred on reads.
>> - Update adi, cdns, dw, mipi-i3c-hci, and renesas controller drivers to
>> populate actual_len on read transfers without mutating len.
>> - Update mctp-i3c to read xfer.actual_len instead of xfer.len.
>>
>> Co-developed-by: Meagan Lloyd <meaganlloyd@linux.microsoft.com>
>> Signed-off-by: Meagan Lloyd <meaganlloyd@linux.microsoft.com>
>> Signed-off-by: Sam Agazaryan <samagazaryan@google.com>
>> ---
>> drivers/i3c/master/adi-i3c-master.c | 5 ++++-
>> drivers/i3c/master/dw-i3c-master.c | 2 +-
>> drivers/i3c/master/i3c-master-cdns.c | 5 ++++-
>> drivers/i3c/master/mipi-i3c-hci/core.c | 2 +-
>> drivers/i3c/master/renesas-i3c.c | 3 +++
>> drivers/net/mctp/mctp-i3c.c | 10 +++++-----
>
> There are not dependence, suppose mctp-i3c.c change go through other tree
> It'd better use sperate patch to fix it.
Isn't mctp-i3c.c dependent on the len -> actual_len change in
any of the master drivers?
next prev parent reply other threads:[~2026-09-28 10:43 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-21 23:05 [PATCH v5 0/5] i3c: add i3cdev module to expose i3c dev in /dev Sam Agazaryan
2026-09-21 23:05 ` [PATCH v5 1/5] i3c: master: export i3c_masterdev_type Sam Agazaryan
2026-09-21 23:06 ` [PATCH v5 2/5] i3c: master: add i3c_for_each_dev helper Sam Agazaryan
2026-09-21 23:06 ` [PATCH v5 3/5] i3c: use actual_len for read transfers Sam Agazaryan
2026-09-24 11:53 ` Adrian Hunter
2026-09-25 15:25 ` Frank Li
2026-09-28 10:42 ` Adrian Hunter [this message]
2026-09-21 23:06 ` [PATCH v5 4/5] i3c: add i3cdev module to expose i3c dev in /dev Sam Agazaryan
2026-09-25 15:38 ` Frank Li
2026-09-21 23:06 ` [PATCH v5 5/5] tools: i3c: add i3ctransfer utility Sam Agazaryan
2026-09-25 9:08 ` [PATCH v5 0/5] i3c: add i3cdev module to expose i3c dev in /dev Andy Shevchenko
2026-09-25 10:57 ` Wolfram Sang
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