3 files changed, 11 insertions, 8 deletions
diff --git a/Documentation/debugging-via-ohci1394.txt b/Documentation/debugging-via-ohci1394.txt
index fa0151a712f..5c9a567b3fa 100644
@@ -25,9 +25,11 @@ using data transfer rates in the order of 10MB/s or more.
With most FireWire controllers, memory access is limited to the low 4 GB
of physical address space. This can be a problem on IA64 machines where
memory is located mostly above that limit, but it is rarely a problem on
-more common hardware such as x86, x86-64 and PowerPC. However, at least
-Agere/LSI FW643e and FW643e2 controllers are known to support access to
-physical addresses above 4 GB.
+more common hardware such as x86, x86-64 and PowerPC.
+At least LSI FW643e and FW643e2 controllers are known to support access to
+physical addresses above 4 GB, but this feature is currently not enabled by
Together with a early initialization of the OHCI-1394 controller for debugging,
this facility proved most useful for examining long debugs logs in the printk
@@ -101,8 +103,9 @@ Step-by-step instructions for using firescope with early OHCI initialization:
compliant, they are based on TI PCILynx chips and require drivers for Win-
dows operating systems.
- The mentioned kernel log message contains ">4 GB phys DMA" in case of
- OHCI-1394 controllers which support accesses above this limit.
+ The mentioned kernel log message contains the string "physUB" if the
+ controller implements a writable Physical Upper Bound register. This is
+ required for physical DMA above 4 GB (but not utilized by Linux yet).
2) Establish a working FireWire cable connection:
diff --git a/drivers/firewire/core.h b/drivers/firewire/core.h
index c98764aeeec..f477308b6e9 100644
@@ -237,8 +237,8 @@ static inline bool is_next_generation(int new_generation, int old_generation)
#define LOCAL_BUS 0xffc0
-/* arbitrarily chosen maximum range for physical DMA: 128 TB */
-#define FW_MAX_PHYSICAL_RANGE (128ULL << 40)
+/* OHCI-1394's default upper bound for physical DMA: 4 GB */
+#define FW_MAX_PHYSICAL_RANGE (1ULL << 32)
void fw_core_handle_request(struct fw_card *card, struct fw_packet *request);
void fw_core_handle_response(struct fw_card *card, struct fw_packet *packet);
diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
index 8db66321956..586f2f7f699 100644
@@ -3716,7 +3716,7 @@ static int pci_probe(struct pci_dev *dev,
version >> 16, version & 0xff, ohci->card.index,
ohci->n_ir, ohci->n_it, ohci->quirks,
reg_read(ohci, OHCI1394_PhyUpperBound) ?
- ", >4 GB phys DMA" : "");
+ ", physUB" : "");