On Sat, Feb 23, 2019 at 10:57 AM Steve Kargl < sgk_at_troutmask.apl.washington.edu> wrote: > Supposely, the laptop only has 4 GB of memory. Not sure how > it finds memory above 4 GB. > Some older chipsets had a 'hole' in memory that they mapped the PCI bus into and then remapped RAM in that range up above the 4GB boundary. That's how it can find memory above 4GB when you have only 4GB of RAM. I hit it with the PC Card stuff I did back in the day since it broke certain heuristics I had in the code that turned out to be unwise for many reasons (not just this one). I don't recall all the details, since it's been so long ago. So I think kib_at_ is right when he highlights > +0x0000000100000000 - 0x000000011ffe7fff, 536772608 bytes (131048 pages) as the memory, since this is indeed above the 4GB limit. It's about 128k of 4k pages (just shy of the 131072 I'd expect), which is a surprisingly round number. Also one that's easy to implement in hardware. So it certainly "smells" the same... That's why I agree with others that hw.above4g_allow=0 is worth a shot, for at least diagnostic purposes. This memory wasn't used before and if it's used now by the drm drivers, and those aren't PAE safe (meaning they cope with allocations beyond 4GB), then that's quite useful to know. Or maybe it's a different driver hating things and stomping on video memory due to wrap around. WarnerReceived on Sat Feb 23 2019 - 18:04:11 UTC
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