https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=231760
John Baldwin <[email protected]> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |[email protected] --- Comment #16 from John Baldwin <[email protected]> --- I got access to two laptops at BSDCan tonight and figured out the bug. I'll clean up the patch I came up with and post it soonish. However, the short version is that the _PIC method in ACPI called a function that directly accessed PCI config registers via the MCFG mapping to clear a bit when enabling APIC mode. However, since the BIOS didn't use PCI config space but directly accessed MCFG directly via SystemMemory, AcpiOsMapMemory was used to map MCFG. This called pmap_mapbios() which remapped the MCFG window as Write-Back instead of UC and the laptops hung right after this. The fix is to add yet another variant of pmap_mapdev() which leaves the existing PAT mode alone and doesn't change it and change AcpiOsMapMemory to use that instead of pmap_mapbios. -- You are receiving this mail because: You are the assignee for the bug. _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-bugs To unsubscribe, send any mail to "[email protected]"
