Messages in this thread | | | From | "Luck, Tony" <> | Subject | RE: [PATCH] EDAC/Intel: Fix shift-out-of-bounds when DIMM/NVDIMM is absent | Date | Tue, 16 May 2023 17:12:29 +0000 |
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>> [ 13.875282] Hardware name: HP HP Z4 G5 Workstation Desktop PC/8962, > > BIOS U61 Ver. 01.01.15 04/19/2023
>> When a DIMM slot is empty, the read value of mtr can be 0xffffffff, therefore
> Looked like a buggy BIOS/hw that didn't set the mtr register. > > 1. Did you print the mtr register whose value was 0xffffffff? > 2. Can you take a dmesg log with kernel "CONFIG_EDAC_DEBUG=y" enabled? > 3. What was the CPU? Please take the output of "lscpu". > 4. Did you verify your patch that the issue was fixed on your systems?
I wonder if BIOS is "hiding" some devices from the OS? The 0xffffffff return is the standard PCI response for reading a non-existent register. But that doesn't quite make sense with having a "dimm present" bit in the MTR register. If the register only exists if the DIMM is present, then there is no need for a "dimm present" bit.
Some "lspci" output may also be useful.
-Tony
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