linux-kernel - Re: [PATCH 1/3] hwmon: spd5118: Do not fail resume on temporary I2C errors

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <f9a4e815-bb21-468b-9568-b4acfd792527@roeck-us.net>
Date: Fri, 30 Jan 2026 17:21:13 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: Kurt Borja <kuurtb@...il.com>,
 TINSAE TADESSE <tinsaetadesse2015@...il.com>
Cc: Armin Wolf <W_Armin@....de>,
 "linux-hwmon@...r.kernel.org" <linux-hwmon@...r.kernel.org>,
 linux-kernel@...r.kernel.org, Guenter Roeck <groeck7@...il.com>
Subject: Re: [PATCH 1/3] hwmon: spd5118: Do not fail resume on temporary I2C
 errors

Hi Kurt,

On 1/30/26 16:55, Kurt Borja wrote:
> On Tue Jan 27, 2026 at 6:41 PM -05, Guenter Roeck wrote:
>> Hi,
>>
>> On Tue, Jan 27, 2026 at 10:23:24PM +0300, TINSAE TADESSE wrote:
>>>
>>> Disabling CONFIG_SENSORS_SPD5118_DETECT completely avoids the issue on
>>> affected platforms,
>>> even without any code changes. This confirms that the failures are
>>> triggered specifically by automatic
>>> SPD5118 instantiation on systems where the i801 controller enforces
>>> SPD Write Disable.
>>
>> Thanks for confirming. Can you try if the patch below fixes the problem ?
>> It is a wild shot, but it might be worth a try.
>>
>> Thanks,
>> Guenter
>>
>> ---
>>  From b44c31c2c779a67827e3144b818cf21f5efacea1 Mon Sep 17 00:00:00 2001
>> From: Guenter Roeck <linux@...ck-us.net>
>> Date: Tue, 27 Jan 2026 15:32:32 -0800
>> Subject: [PATCH] hwmon: (spd5118) Explicitly enable temperature sensor in
>>   probe function
>>
>> Instantiating the driver does not make sense if the temperature sensor
>> is disabled, so enable it unconditionally in the probe function.
>>
>> If that fails, write operations to the chip are likely disabled
>> by the I2C controller. Bail out with an eror message if that happens.
>>
>> Signed-off-by: Guenter Roeck <linux@...ck-us.net>
>> ---
>>   drivers/hwmon/spd5118.c | 5 +++++
>>   1 file changed, 5 insertions(+)
>>
>> diff --git a/drivers/hwmon/spd5118.c b/drivers/hwmon/spd5118.c
>> index 5da44571b6a0..3e0e780014f9 100644
>> --- a/drivers/hwmon/spd5118.c
>> +++ b/drivers/hwmon/spd5118.c
>> @@ -552,6 +552,11 @@ static int spd5118_common_probe(struct device *dev, struct regmap *regmap,
>>   	if (!spd5118_vendor_valid(bank, vendor))
>>   		return -ENODEV;
>>   
>> +	if (regmap_update_bits(regmap, SPD5118_REG_TEMP_CONFIG,
>> +			       SPD5118_TS_DISABLE, 0) < 0)
>> +		return dev_err_probe(dev, -ENODEV,
>> +				     "Failed to enable temperature sensor\n");
>> +
>>   	data->regmap = regmap;
>>   	mutex_init(&data->nvmem_lock);
>>   	dev_set_drvdata(dev, data);
> 
> Hi Guenter,
> 
> I'm experiencing the same issue reported in this thread. This patch does
> not fix it for me :(.
> 
Thanks for a note. Well, it was a wild shot, so it is not entirely surprising
that it didn't work. I suspect regmap doesn't actually write the register
if the value is unchanged. Another option might be to try writing a value
(e.g., 0x01) into register 0x13 or 0x14. Those are "clear status" registers.
If that fails, we would know that the chip is write protected.

Thanks,
Guenter