't mind.

  While attempting to run mythtv in a xen domU, I encountered problems
  loading the driver for my saa7134 card, with an error from ioremap().

  This error was due to the driver allocating an incorrectly sized mmio
  area, which was trapped by xen's permission checks, but this would go
  un-noticed on a kernel without xen.

  My card has a 1K sized mmio area, I've had information that other cards
  have 2K areas, perhaps others have different sizes, yet the driver
  always attempts to map 4K.  I realise that the granularity of mapping is
  the page size, which typically would be 4K, but unless the card's base
  address happens to fall on a 4K boundary (mine does not) then the
  base+4K will end up spanning two pages, and this is when the error
  occurs under xen.

  My patch uses the pci_resource_len macro to determine the size required
  for the user's particular card, instead of the hardcoded 4K value. I've
  tested with a couple of printk() inside ioremap() that the start address
  and size do get rounded to the closest page boundary.

  With this patch I am able to successfully load the saa7134 driver and
  run mythtv under xen with my card, subject to correct pollirq settings
  in case of shared IRQ, I am still seeing occasional DMA panics, which I
  think are related to swiotlb handling by dom0/domU, usually the panic
  occurs when changing mux, once tuned to a mux, 12 hour continuous
  recordings are possible without errors.

Reported-by: Alexey Fisher <bug-track@fisher-privat.net>
Tested-by: Alexey Fisher <bug-track@fisher-privat.net>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Andy Burns <andy@burns.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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