x86/setup: Move trim_snb_memory() later in setup_arch() to fix boot hangs

Commit

  a799c2bd29d1 ("x86/setup: Consolidate early memory reservations")

moved reservation of the memory inaccessible by Sandy Bride integrated
graphics very early, and, as a result, on systems with such devices
the first 1M was reserved by trim_snb_memory() which prevented the
allocation of the real mode trampoline and made the boot hang very
early.

Since the purpose of trim_snb_memory() is to prevent problematic pages
ever reaching the graphics device, it is safe to reserve these pages
after memblock allocations are possible.

Move trim_snb_memory() later in boot so that it will be called after
reserve_real_mode() and make comments describing trim_snb_memory()
operation more elaborate.

 [ bp: Massage a bit. ]

Fixes: a799c2bd29d1 ("x86/setup: Consolidate early memory reservations")
Reported-by: Randy Dunlap <[email protected]>
Signed-off-by: Mike Rapoport <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Tested-by: Randy Dunlap <[email protected]>
Tested-by: Hugh Dickins <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

0 files changed, 0 insertions, 0 deletions