[PATCH 1/2] firewire: ohci: fix Agere FW643 and multiple cameras

From: Stefan Richter
Date: Fri Aug 28 2009 - 07:25:43 EST

From: Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx>
Subject: firewire: ohci: fix Agere FW643 and multiple cameras

An Agere FW643 OHCI 1.1 card works fine for video reception from one
camera but fails early if receiving from two cameras. After a short
while, no IR IRQ events occur and the context control register does not
react anymore. This happens regardless whether both IR DMA contexts are
dual-buffer or one is dual-buffer and the other packet-per-buffer.

This can be worked around by disabling dual buffer DMA mode entirely.

Reported-by: Samuel Audet <samuel.audet@xxxxxxxxx>
Signed-off-by: Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx>
drivers/firewire/ohci.c | 9 +++++++++
1 file changed, 9 insertions(+)

Index: linux-2.6.31-rc8/drivers/firewire/ohci.c
--- linux-2.6.31-rc8.orig/drivers/firewire/ohci.c
+++ linux-2.6.31-rc8/drivers/firewire/ohci.c
@@ -34,6 +34,7 @@
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/pci.h>
+#include <linux/pci_ids.h>
#include <linux/spinlock.h>
#include <linux/string.h>

@@ -2372,6 +2373,9 @@ static void ohci_pmac_off(struct pci_dev
#define ohci_pmac_off(dev)
#endif /* CONFIG_PPC_PMAC */

+#define PCI_DEVICE_ID_AGERE_FW643 0x5901
static int __devinit pci_probe(struct pci_dev *dev,
const struct pci_device_id *ent)
@@ -2422,6 +2426,11 @@ static int __devinit pci_probe(struct pc
version = reg_read(ohci, OHCI1394_Version) & 0x00ff00ff;
ohci->use_dualbuffer = version >= OHCI_VERSION_1_1;

+ /* dual-buffer mode is broken if more than one IR context is active */
+ if (dev->vendor == PCI_VENDOR_ID_AGERE &&
+ dev->device == PCI_DEVICE_ID_AGERE_FW643)
+ ohci->use_dualbuffer = false;
/* x86-32 currently doesn't use highmem for dma_alloc_coherent */
#if !defined(CONFIG_X86_32)
/* dual-buffer mode is broken with descriptor addresses above 2G */

Stefan Richter
-=====-==--= =--- ===--

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