Hi!
2024-01-10 at 21:13, Heiner Kallweit wrote:
> If this is an adapter on a muxed bus segment, assume that each segment
> is connected to a subset of the (> 8) overall memory slots. In this
> case let's probe the maximum of 8 slots, however stop if the number
> of overall populated slots is reached.
>
> If we're not on a muxed segment and the total number of slots is > 8,
> report an error, because then not all SPD eeproms can be addressed.
> Presumably the bus is muxed, but the mux config is missing.
>
> Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
> ---
> drivers/i2c/i2c-smbus.c | 19 ++++++++++++-------
> 1 file changed, 12 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c
> index 74807c6db..e94714d5a 100644
> --- a/drivers/i2c/i2c-smbus.c
> +++ b/drivers/i2c/i2c-smbus.c
> @@ -351,13 +351,18 @@ void i2c_register_spd(struct i2c_adapter *adap)
> if (!dimm_count)
> return;
>
> - dev_info(&adap->dev, "%d/%d memory slots populated (from DMI)\n",
> - dimm_count, slot_count);
> -
> - if (slot_count > 8) {
> - dev_warn(&adap->dev,
> - "Systems with more than 8 memory slots not supported yet, not instantiating SPD\n");
> - return;
> + /* Check whether we're a child adapter on a muxed segment */
> + if (i2c_parent_is_i2c_adapter(adap)) {
> + if (slot_count > 8)
> + slot_count = 8;'
The comment "Only works on systems with 1 to 8 memory slots" above
i2c_register_spd() is now incorrect and needs adjusting.
> + } else {
> + dev_info(&adap->dev, "%d/%d memory slots populated (from DMI)\n",
> + dimm_count, slot_count);
> + if (slot_count > 8) {
> + dev_err(&adap->dev,
> + "More than 8 memory slots on a single bus, mux config missing?\n");
> + return;
> + }
> }
>
> /*
The loop below this hunk is limited by dimm_count, but it is checked
separately for each muxed segment. It is therefore now possible to
instantiate a total number of slots larger than the dimm_count.
That was not possible before. I don't know if that's a problem, but
the check have been (silently) relaxed.
Cheers,
Peter
