[coreboot] AMD UMA questions

Rudolf Marek r.marek at assembler.cz
Fri Nov 11 18:33:35 CET 2011

Hi guys,

I'm ccining coreboot ml. I still struggle with the flicker during LDTSTOP 
transitions on 785G (PCI ID 0x9710 of uma and NB same as RS880). I suspect that 
I need to setup something in graphics engine. I checked all possible settings in 
NB/SB so I guess it must be something which is set in gfx.c

<------>/* Force allow LDT_STOP Cool'n'Quiet workaround. */
<------>*(GpuF0MMReg + 0x655c/4) |= 1<<4;

I think those bits are read only on my system. Maybe it is something else.
Any idea what to do with that? It seems it needs access to some more advanced 


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