From: Jean Delvare <jdelvare@suse.de>
To: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Cc: Linux I2C <linux-i2c@vger.kernel.org>,
Mika Westerberg <mika.westerberg@linux.intel.com>,
Wolfram Sang <wsa@the-dreams.de>
Subject: Re: [PATCH v2] i2c: i801: Fix I2C Block Read on 8-Series/C220 and later
Date: Tue, 11 Oct 2016 20:20:45 +0200 [thread overview]
Message-ID: <20161011202045.43787f2e@endymion> (raw)
In-Reply-To: <eb3c0e91-5744-3b49-515e-dd68ed5d88aa@linux.intel.com>
Hi Jarkko,
On Tue, 11 Oct 2016 14:32:55 +0300, Jarkko Nikula wrote:
> On 10/11/2016 02:13 PM, Jean Delvare wrote:
> > Starting with the 8-Series/C220 PCH (Lynx Point), the SMBus
> > controller includes a SPD EEPROM protection mechanism. Once the SPD
> > Write Disable bit is set, only reads are allowed to slave addresses
> > 0x50-0x57.
> >
> > However the legacy implementation of I2C Block Read since the ICH5
> > looks like a write, and is therefore blocked by the SPD protection
> > mechanism. This causes the eeprom and at24 drivers to fail.
> >
> > So assume that I2C Block Read is implemented as an actual read on
> > these chipsets. I tested it on my Q87 chipset and it seems to work
> > just fine.
> >
> > Signed-off-by: Jean Delvare <jdelvare@suse.de>
> > Cc: Jarkko Nikula <jarkko.nikula@linux.intel.com>
> > Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
> > Cc: Wolfram Sang <wsa@the-dreams.de>
> > ---
> > Changes since v1:
> > * Rebased on Linus' latest tree.
> >
> > Jarkko, still no information about this from your Windows or hardware
> > folks?
>
> No update, in fact some of the contacts have left the company :-(
What do we do then? Without this patch, I2C Block Read doesn't work at
all on recent chipsets. I don't think it can be worse with the patch.
And it works fine on the few machines I tested on. So I would like this
patch to go upstream.
My coverage is limited though. Did anyone at Intel test this patch on
other (recent) systems?
--
Jean Delvare
SUSE L3 Support
next prev parent reply other threads:[~2016-10-11 18:20 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-11 11:13 [PATCH v2] i2c: i801: Fix I2C Block Read on 8-Series/C220 and later Jean Delvare
2016-10-11 11:32 ` Jarkko Nikula
2016-10-11 18:20 ` Jean Delvare [this message]
2016-10-17 12:38 ` Jarkko Nikula
2016-10-17 12:38 ` Jarkko Nikula
2016-10-25 10:02 ` Wolfram Sang
2016-10-26 12:15 ` Jean Delvare
2016-10-26 12:51 ` Wolfram Sang
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