diff options
| -rw-r--r-- | drivers/firewire/ohci.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c index 8bf89267dc25..d731b413cb2c 100644 --- a/drivers/firewire/ohci.c +++ b/drivers/firewire/ohci.c @@ -1130,7 +1130,13 @@ static int context_add_buffer(struct context *ctx) return -ENOMEM; offset = (void *)&desc->buffer - (void *)desc; - desc->buffer_size = PAGE_SIZE - offset; + /* + * Some controllers, like JMicron ones, always issue 0x20-byte DMA reads + * for descriptors, even 0x10-byte ones. This can cause page faults when + * an IOMMU is in use and the oversized read crosses a page boundary. + * Work around this by always leaving at least 0x10 bytes of padding. + */ + desc->buffer_size = PAGE_SIZE - offset - 0x10; desc->buffer_bus = bus_addr + offset; desc->used = 0; |