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Message-ID: <4e09b843-3d2d-46d7-a8e1-2eabc4382dc7@roeck-us.net>
Date: Mon, 17 Jun 2024 08:49:30 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Paul Menzel <pmenzel@...gen.mpg.de>
Cc: linux-hwmon@...r.kernel.org, linux-i2c@...r.kernel.org,
linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
Krzysztof Kozlowski <krzk+dt@...nel.org>,
Wolfram Sang <wsa+renesas@...g-engineering.com>,
René Rebe <rene@...ctcode.de>,
Thomas Weißschuh <linux@...ssschuh.net>,
Armin Wolf <W_Armin@....de>,
Stephen Horvath <s.horvath@...look.com.au>
Subject: Re: [PATCH v4 5/6] i2c: smbus: Support DDR5 SPD EEPROMs
Hi Paul,
On Mon, Jun 17, 2024 at 04:42:47PM +0200, Paul Menzel wrote:
[ ... ]
>
> I applied your patch
>
> $ git log --oneline --no-decorate -2
> 00058a6 eeprom: Add basic spd5118 support
> a0e5865 i2cdetect: only use "newer" I2C_FUNC_* flags if they exist
>
> but reading eeprom fails:
>
> $ sudo ./eeprom/decode-dimms
decode-dimms does not need sudo, but that should not make a difference.
> Cannot read /sys/bus/i2c/drivers/spd5118/0-0050/eeprom at
> ./eeprom/decode-dimms line 2465.
>
Well, it _is_ a hack ;-), but that specific operation should not fail.
Please try the following:
ls -l /sys/bus/i2c/drivers/spd5118/0-0050/eeprom
cp /sys/bus/i2c/drivers/spd5118/0-0050/eeprom /tmp
od -t x1 /sys/bus/i2c/drivers/spd5118/0-0050/eeprom
sudo i2cdump -y -f 0 0x50
All those should work, and the size of /tmp/eeprom should be
1024 bytes. The output of i2cdump should start with something like
0 1 2 3 4 5 6 7 8 9 a b c d e f 0123456789abcdef
00: 51 18 0a 86 32 03 32 00 00 00 00 07 ff 7f 00 00 Q???2?2......?..
^^
and with
0 1 2 3 4 5 6 7 8 9 a b c d e f 0123456789abcdef
00: 51 18 0a 86 32 03 32 00 00 00 00 00 ff 7f 00 00 Q???2?2......?..
^^
after executing the "sensors" command.
Other than that, I can see that your system is an Intel system,
meaning the i2c controller would be i801, not piix4. I wonder
if that makes a difference. Has anyone else seeing this tested
eeprom access with i801 (or any other controller besides piix4),
by any chance ?
Thanks,
Guenter
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