CCing Heiner... > > > > Yes, maybe this could be simplified to "(LP)DDR memory types" > > > > > > > > > > I rephrased it to "Only works for (LP)DDR memory types up to DDR5". > > > > Thanks! > > > > > How about "Only works on systems with 1 to 8 memory slots" ? > > > > This is a question for Heiner. I'd think it is is still correct, but I > > don't know exactly. > > > > My interpretation was that it should work if the DIMMs are connected to > multiplexed I2C busses, but probably not if they are connected to > different adapters. The error message in that case is a bit misleading, > though, because it claims that "More than 8 memory slots on a single bus", > which isn't necessarily the case. For example, it should be perfectly valid > to have up to 24 DIMMs in this system. > > i2c-0/name:SMBus PIIX4 adapter port 0 at 0b00 > i2c-1/name:SMBus PIIX4 adapter port 2 at 0b00 > i2c-2/name:SMBus PIIX4 adapter port 1 at 0b20 > > ... but I guess that is a question for someone with such a system to answer. > > Ultimately the handling of systems with more than 8 memory slots will need > to be updated at some point. On my systems, with 'i2c: piix4: Register SPDs' > applied, I see > > i2c i2c-0: 4/4 memory slots populated (from DMI) > [my system is running 6.6.y which still generates that message] > i2c i2c-0: Successfully instantiated SPD at 0x50 > i2c i2c-0: Successfully instantiated SPD at 0x51 > i2c i2c-0: Successfully instantiated SPD at 0x52 > i2c i2c-0: Successfully instantiated SPD at 0x53 > i2c i2c-1: 4/4 memory slots populated (from DMI) > i2c i2c-2: 4/4 memory slots populated (from DMI) > > meaning the function is called for each adapter (which makes sense). > However, the code counting the DIMMs doesn't really take the adapter > into account, meaning adapters 1 and 2 are still probed even though > all DIMMs were already instantiated from adapter 0. > > On a system with more than 8 DIMMs connected to different piix4 adapters > (without mux) we'd probably see something like > > i2c i2c-0: More than 8 memory slots on a single bus, contact i801 maintainer ... > i2c i2c-1: More than 8 memory slots on a single bus, contact i801 maintainer ... > i2c i2c-2: More than 8 memory slots on a single bus, contact i801 maintainer ... > > which wouldn't be very helpful. I think the main problem may be that > the i801 driver implements sub-adapters as muxes, but the piix4 driver > doesn't do (or need) that. The message is also i801 centric which doesn't > apply anymore after 'i2c: piix4: Register SPDs' is applied. > > However, I would not want to even try changing that code without access > to a system using piix4 and supporting more than 8 memory slots. > > Thanks, > Guenter > >
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