Question:
It may be the HIGH UMDA Mode 5, that be an problem (timing).
Kernel panic mostly comes up when large / high transferof file (Cloning!).
Normaly work with HD didnt give kernel panic.
So can somebody (which made this AppleIntelPIIXATA.kext (within IOATA.familiy) limit UMDA to 4 ?
Would give no big performance problems on normal work and work with small files.
I found that in AppleIntelPIIXATATiming.h it may the easiest way to change that.
change line
{ 5, 1, 16, 1, 20, kPIIX_PCI_IDECONFIG_FAST_PCB0 }
into
{ 5, 2, 8, 2, 30, kPIIX_PCI_IDECONFIG_PCB0 } (same as 4)
static const PIIXUDMATiming
piixUDMATiming[] =
{
/* Mode CT RP UDMATIM Cycle U-DMA Clock */
{ 0, 4, 6, 0, 120, 0 },
{ 1, 3, 5, 1, 90, 0 },
{ 2, 2, 4, 2, 60, 0 },
{ 3, 3, 8, 1, 45, kPIIX_PCI_IDECONFIG_PCB0 },
{ 4, 2, 8, 2, 30, kPIIX_PCI_IDECONFIG_PCB0 },
{ 5, 1, 16, 1, 20, kPIIX_PCI_IDECONFIG_FAST_PCB0 }
};
Sure, would be better to change/limit UMDA to Mode 4 in some .cpp code, because
IOREGISTRY would show UMDA 5 Mode, and we didnt know if it is an Patched Mode 5 (to 4)